JPH03154542A - Ring type local area network - Google Patents

Abstract

PURPOSE:To ensure the communication as to a subsequent station located in advance from a area fault occurrence position by providing a standby management station so as to send a command of a loopback to the subsequent station disconnected of an input signal in the occurrence of a fault and allowing the standby management station to execute the loopback processing. CONSTITUTION:A standby management station 4 is connected to a management station 3 by a private line 5 and in the through state normally and releases its through state according to a command sent via the private line 5 from the management station 3 detecting a fault. Then a loopback command is sent to slave stations 1a-1d whose input signal is interrupted and the station 4 executes the loopback processing to reconstitute a new ring from that of the management station 3 while being arranged to a prescribed location in a ring. Thus, the communication between subsequent stations arranged before a fault occurrence location is ensured.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention applies to a ring-type local area network (Local Area Network) with duplex transmission paths.
(hereinafter referred to as LAN).

[Conventional technology]

Figure 7 is, for example, the 9th volume of the Information Processing Society of Japan's ``Local Area Network'' Symposium Proceedings (September 1988).
9 is a block diagram showing a conventional ring type LAN shown on pages 9 to 105. FIG. In the figure, 1a to 1d are a plurality of dependent stations that multiplex terminal data into a ring transmission frame, and 2& and 2b are upper and lower stations that connect these dependent stations 1a to 1d to form a ring. It is a transmission line. 3
is placed at a predetermined position in the ring, that is, between the dependent stations 1a and 1d, and transmits the uplink and downlink transmission lines 2a and 2bK synchronization signals and ring transmission frames, and also returns When receiving the synchronization signal and ring transmission frame, monitoring each dependent station 1a to 1d and detecting an abnormality, the dependent stations 18 to 1d whose input signal was cut off
It is a management station that sends loopback commands to the network and also executes loopback processing itself.

Next, I will explain the operation□. Under normal conditions, the management station 3 is in a through state, and data received from the upper transmission line 2a is sent as is to the upper transmission line 2a, and data received from the lower transmission line 2b is sent as is to the lower transmission line. transmission path 2b
is being sent to. It also sends out a predetermined synchronization signal and ring transmission frame to the upstream and downstream transmission lines 2a and 2b, receives the synchronization signal and ring transmission frame that are returned after one cycle, and uses the ring to send out the synchronization signal and ring transmission frame to each dependent station 1a to 1d is being monitored.

Here, as shown in Fig. 8, if a section fault occurs between dependent stations 1b and 10, and the upper and lower transmission lines 2a and 2b between them are disconnected (indicated by X in the figure), ), when the management station 3 detects this abnormality through the above-mentioned monitoring, it sends a loopback command to the dependent station 1bK whose input signal has been cut off. Normally, a transmission line 2a returns from the dependent station 1d to the management station 3.

2b is laid close to the transmission lines 2a and 2b connecting the dependent stations 1a to 1d, so there is a high possibility that all four lines will be disconnected at the same time. The slave station 1b that receives this command executes loopback processing and sends the output signal of the upper transmission line 2a to the output side of the lower transmission line 2b where the input signal is cut off. Further, the management station 3 sends a loopback instruction to the dependent station 1b, and also executes the loopback process itself, and sends an output signal to be sent to the downstream transmission path 2b to the upstream transmission path 2aK.

Accordingly, dependent station 1 up to the location where the section fault has occurred
The ring between a, 1b and the management station 3 is reconfigured, and communication between them is ensured.

[Problem to be solved by the invention]

Since the conventional ring type LAN is configured as described above, the dependent station 1c located ahead of the section failure location,
There was a problem in that 1d fell out of the reconfigured ring, making it impossible to secure communication.

This invention was made in order to solve the above-mentioned problem, and for the dependent stations located earlier than the section fault occurrence position, the ring is separately reconfigured and communication between them is established. The purpose is to obtain a ring-type LAN that can be secured.

Another invention of the present invention is to obtain a ring-type LAN that can ensure communication between all dependent stations even if a section failure occurs by connecting two reconfigured rings using a failure detour route. The purpose is to

[Means to solve the problem]

The ring type LAN according to the invention described in claim (1) is connected to a management station via a dedicated line, is in a through state during normal operation, and is connected to a management station according to instructions sent via the dedicated line from the management station that detects an abnormality. In addition to canceling the through state, it sends a loopback command to the subordinate station whose input signal was cut off, and also performs loopback processing itself to reconfigure a new ring independently from the management station. A standby management station is placed at a predetermined position within the ring.

The ring type LAN according to the invention described in claim (2) is further connected to each other by a detour path and inserted into a predetermined transmission path within the ring, and is in a through state during normal times, and is released from the through state when an abnormality occurs. However, a failure detour device is provided which forms a failure detour route that connects the newly reconfigured ring of the management station and the standby management station using the detour path.

[Effect]

The standby control station in the invention described in claim (1) is placed in a through state at a predetermined position within the ring during normal times, and is placed in a through state at a predetermined position in the ring during an abnormality in accordance with an instruction sent from a management station via a dedicated line. When the input signal is cut off and the input signal is cut off, the loopback command is sent to the nine subordinate stations, and the subordinate station itself executes the loopback process. Regarding the stations, a ring different from the ring reconfigured by the management station is reconfigured to ensure communication between them.

Further, the failure detour device in the invention as claimed in claim (2) is connected to each other by a detour path and inserted into a predetermined transmission path within a ring, and is in a through state during normal operation, and when a failure occurs in the ring, the failure detour device is inserted into a predetermined transmission path within a ring. By canceling the state and forming a failure detour route using the detour path, the ring reconfigured by the management station and the ring reconfigured by the standby management station are connected by this failure detour route. , ensuring communication between all dependent stations.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1a to 1d are dependent stations, and 2a is a dependent station.

2b is a transmission path, and 3 is a management station, which are the same or equivalent parts as those in the conventional system which are given the same reference numerals in FIG. 7, and therefore detailed explanation will be omitted.

4 connects the dependent stations 1a to 1d and the management station 3 to the transmission line 2.
It is placed at a predetermined position within the ring formed by connecting with aw2b, that is, between the dependent station 1d and the management station 3, and is in a through state during normal times, and is sent from the management station 3 that detects an abnormality. It is a standby management station that cancels the through state according to instructions, sends a loopback command to the dependent stations 1a to 1dK whose input signals have been cut off, and also executes loopback processing itself. In the illustrated embodiment, only one standby management station 4 is installed, but it is also possible to install a plurality of stations.

Further, reference numeral 5 denotes a dedicated line that connects the management station 3 and this standby management station 4 and transmits instructions from the management station 3 to this standby management station 4.

Next, the operation will be explained. Under normal conditions, the management station 3 is in a through state, and data received from the upper transmission line 2a is sent as is to the upper transmission line 2a, and data received from the downstream transmission line 2b is sent to the upper transmission line 2a. Lower transmission line 2b
is being sent to. (9) Send a predetermined synchronization signal and ring transmission frame to the upstream and downstream transmission paths 2a and 2b in synchronization with the leased line 5, and receive the synchronization signal and ring transmission frame that have returned after going around. , and monitors each dependent station 11-1d using a ring. The standby management station 4 is also in the through state, and the data received from the upstream transmission line 2a is sent to the upper transmission line 2a and then to the lower transmission line 2b.
The data received from the terminals are sent as they are to the downstream transmission path 2b. It also monitors ring synchronization signals, intercepts ring transmission frames, and intercepts leased lines 5.

Here, as shown in Fig. 2, if a section fault occurs between dependent stations 1b and 10 and the upper and lower transmission lines 2a*2b between them are disconnected (in the figure, the x marks indicate ), when the management station 3 detects this abnormality, it gives a loopback command to the slave station 1b whose input signal has been cut off, and also sends an instruction to cancel the through state and perform loopback control operation via the dedicated line 5. is given to the standby management station 4. At this time, the failure information collected by the management station 3 is also simultaneously transmitted to the standby management station 4 as additional information. The standby management station 4 that received this instruction
Similarly, a loopback command is given to the dependent station 1cK whose input signal has been cut off.

The management station 3 and the dependent station 1b that received the command from the management station 3 each execute loopback processing as in the conventional case, and the dependent station 1b returns to the position where the section fault has occurred.
*1 The ring is reconfigured by b and management station 3.

On the other hand, the dependent station 1c that received the command from the standby management station 4 executes loopback processing and transfers the output signal of the lower transmission line 2b to the output side of the upstream transmission line 2& where the input signal is disconnected. The sending and standby management station 4 also executes loopback processing and sends the output signal to be sent to the upstream transmission path 2a to the downstream transmission path 2b. As a result, the ring including the dependent stations 1c and 1d and the standby management station 4 up to the location where the section failure has occurred is reconfigured.

After the ring is reconfigured in this way, two L
Depending on the way the AN operates, communication is ensured between subordinate stations belonging to each ring. At this time, since the management station 3 and the standby management station 4 generate synchronization signals in synchronization with the reception clock from the dedicated line 5, the signal phases are unified in all the dependent stations 1a to 1d of these two LANs.

In addition, if the leased line 5 becomes a failure and only part of the upstream and downstream transmission lines 2a and 2b of the ring is disconnected, but no section failure occurs, the management station 3 requests the standby management station 4 to The live transmission line of the ring.

2b, instructions for canceling the through state and loopback control operation are given.

FIG. 3 is a block diagram showing another embodiment of the invention. In the figure, 1a to 1d are dependent stations, 2a+2bfi transmission lines, 3 a management station, and 4 a standby management station, which are equivalent to those given the same reference numerals in FIG.

Reference numeral 6 denotes a detour path such as a public network, which supplies a synchronized clock to the management station 3 and standby management station 4. 7a
e7b is a predetermined transmission path within the ring, that is, the upper transmission path 2a s between the management station 3 and the dependent station 1a or the dependent station 1.
This is a failure detour device that is inserted into the lower transmission path 2bK between the standby management station 4 and the standby management station 4, and is connected to each other by the detour path 6. The failure bypass devices 7m and 7b are in a through state during normal operation, and when an abnormality occurs in the ring, they are released from the through state and the management station 3 and the standby management station 4 transfer the newly reconfigured ring to the detour route 6. This system connects the network to form a failure detour route. Therefore, this failure bypass device 7 a
It is effective if a 7 b are placed on both sides with a section where there is a high possibility of failure occurring. 8a*8b are terminal devices connected to the dependent station 1b or 1C and exchanging data with each other.

Next, the operation will be explained. FIG. 4 is an explanatory diagram showing the flow of data during normal operation. In the figure, 9 indicates seven frames of ring transmission transmitted within the ring.

Further, 10 is written by the dependent station 1b or 1cK and is checked by the failure bypass devices 7a and 7b, and 11.12 is terminal data 13 from the terminal device 8a or terminal data from the terminal device 8b. 14 is the data area to be praised. Here, the dependent station 1b assigns the return-to-home bit of the terminal device 8a to "0"K, and the dependent station 1C assigns the return-to-home bit of the terminal device 8b to 6.
It is assigned to 1m. In addition, if the fault bypass device 7 & has the self-station return sibit “0”, it is normal; if it is “1”, it is abnormal.
The failure bypass device is set to be normal if the self-return bit is 11''', and abnormal if it is "0".

During normal operation, the terminal data 13 sent from the terminal device 8a and the terminal data 14 sent from the terminal device 8b are transmitted through the transmission line 2 on the upper side of the line 1 as shown by the broken line in FIG.
They are transmitted and received from each other via aK ring. That is, in the subordinate station 1b, bit 10 of the received ring transmission frame S from the upper transmission line 2a is set to "1".
”, so the terminal data 14 from the terminal device 8b is
It is separated from the data area 12 of the ring transmission frame 9 and sent to the terminal device 8a. Additionally, the slave station 1b multiplexes the terminal data 13 from the terminal device 8a into the data area 11 of the ring transmission frame 9, turns on the local station return bit 10, and transmits it to the upper transmission path 2a. do.

As described above, the dependent station 1c assigns the return-to-home bit of the terminal device 8b to "1" and performs the same operation, thereby transmitting the terminal data 13 to the terminal device 8b and transmitting the terminal data 14. The data area 12 of the ring transmission frame 9
The signal is multiplexed into the upper transmission line 2aK and sent out. At this time, in the failure bypass device 7a, the passing ring transmission frame 9
Since bit 10 (return to own station) is "1", it is determined to be normal and the ring transmission frame 9 is passed through as is.

As a result, the ring transmission frame 9 is transmitted to the dependent station 1b.

Here, as shown in FIG. 5, a section failure occurs between the dependent station 1b and the IC, which is indicated by an x mark in the diagram. ), upper and lower transmission lines 2a and 2b between them are disconnected, the second
As in the case shown in the figure, the first management station 3 and the standby management station 4 give a loopback command to the dependent station 1b6 or 1c whose input signal has been cut off, and also execute the loopback process themselves.

In addition, dependent stations 1b and 1C that received the command also execute loopback processing, respectively, so that the two rings of block A and block B shown in FIG. 5 are newly reconfigured. At this time, although the dependent stations 1b and 1c are looping back, the handling of the ring transmission frame 9 is the same as in normal times.

FIG. 6 shows the flow of data in such a state.

In the dependent station 1b, since the local station return bit 10 of the ring transmission frame 9 received over the upper transmission line 2a is '1'', the data area 12 of the ring transmission frame 9 is not connected to the terminal from the multi-terminal device 8b. The dependent station 1b separates the data 14 and sends it to the terminal device 8a.Furthermore, the dependent station 1b multiplexes the terminal data 13 from the terminal device 8a into the data area 11 of the ring transmission frame 9.
0 is rewritten to "0" and transmitted through the lower transmission line 2bK.

This ring transmission frame 9 is looped back at the management station 3 and sent to the failure bypass device 7a. If the self-station return bit 10 is 'O'', the failure detour device γa determines that there is a failure, cancels the through state, and sends the ring transmission 7 frame 9 to the failure detour device 7b via the detour path 6. Detour device 7
B sends the received ring transmission frame 9 to the dependent station 1c via the downlink transmission path 2b.

Since the self-station return bit 10 of the dependent station 1c is "0", the dependent station 1c separates the terminal data 13 from the data area 12 of the ring transmission frame 9 and sends it to the terminal device 8b. Further, the dependent station 1c multiplexes the terminal data 13 from the terminal device 8b into a ring transmission frame 9, rewrites the local station return bit 10 to 11'', and transmits it to the upper transmission path 2a. is looped back at the standby management station 4 and sent to the failure bypass device 7b, and the failure bypass device 7b, which has determined that there is a failure because the self-station return sibit 10 is 11'', sends it to the failure bypass device 7& via the detour path 6. Sent.

The failure bypass device 7a sends the received ring transmission frame 9 to the dependent station 1b via the upper and lower transmission lines 2a.

Even if a section failure occurs in this way, communication between the terminal devices 8a and 8b connected to the dependent stations 1b and 1c of different blocks is ensured by the route shown by the broken line in FIG.

Note that in the above embodiment, an identifier called the local station return p bit is used, but it is also possible to write the node number, terminal number, etc. to identify whether or not data from the local node has arrived at the other node. You may also do so.

〔Effect of the invention〕

As described above, according to the invention recited in claim <1), a standby management station is provided, and the standby management station itself sends a loopback command to a dependent station whose input signal is cut off when a failure occurs. Since the control station is also configured to perform loopback processing, a ring similar to the ring that is reconfigured by the management station is separately reconfigured for dependent stations placed ahead of the section failure location, and this reconfiguration is performed separately. This has the effect of providing a ring-type LAN that can ensure communication within the ring.

Further, according to the invention described in claim (2), when a failure occurs, the separate reconfigured rings by the management station and the standby management station are connected by the failure detour route formed by the failure bypass device using the detour path. With this configuration, it is possible to create a ring-type LA that can ensure communication between all dependent stations.
This has the effect of obtaining N.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a ring type packing N according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a section failure state thereof.
FIG. 3 is a block diagram showing another embodiment of the present invention, and FIG.
Figure 5 is an explanatory diagram showing the data flow during normal operation, Figure 5 is an explanatory diagram showing the section failure state, Figure 6 is an explanatory diagram showing the data flow in the event of an interval failure, and Figure 7 is the conventional ring. Type L
FIG. 8, a block diagram showing the AN, is an explanatory diagram showing the section failure state. 1 a=1 d is a dependent station, 2a and 2b are transmission lines, 3 is a management station, 4 is a standby management station, 5 is a leased line, and 6 is a detour % 7
a e7b is a failure bypass device. τ-1 (2 others) Figure 4 Procedural amendment (voluntary) 1. Display of the case Japanese Patent Application No. 1-294739 2, Name of the invention Ring type local area network 3, Person making the amendment Relationship to the case Patent applicant address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) ) Mitsubishi Electric Co., Ltd. Representative Moriya Shiki Address 6, 1-4-10 Nishi-Shinbashi, Minato-ku, Tokyo, Contents of the amendment (1) "Through state" on page 4, line 7 of the specification and page 9, line 10 Both the words ``in the ring transmission frame'' are corrected to ``replace the data in the received ring transmission frame with the newly generated ring transmission frame''. (2) On page 5, line 2 of the specification, “from dependent station 1d to management station 3
The phrase "return to" is corrected to "up and down between the dependent station 1d and the management station 3." (3) On page 7, line 10 of the specification, "standby control station" is corrected to "standby management station." (4) On page 9, lines 18 to 19 of the specification, the phrase "Similarly, the standby management station 4" is corrected to "the standby management station 4." (5) In the specification, page 9, line 20 and page 10, line 1, “
The words ``data'' are both corrected to ``synchronization signal and ring transmission frame.'' (6) On page 13, line 16 of the specification, “If it is 0, it is normal.
If it is “1”, it is abnormal”, but if it is “°”1”, it is normal.
If it is “0”, it is corrected as “abnormal”. (7) On page 13 of the specification, lines 17 to 18, it says "If it's '1', it's normal; if it's '0', it's abnormal." and correct it. (8) Figures 1, 3, 4, 5, and 6 of the drawings shall be corrected as shown in the attached sheets. 7. List of attached documents l) Document stating the amended Figure 1 2) Document stating the amended Figure 3 3) Document stating the amended Figure 4 4) Document stating the amended Figure 4 5) Document stating Figure 5 after amendment 1 document 1 document 1 document 1 document 1 or more Documents stating Figure 6 after amendment 254-

Claims (2)

[Claims] (1) A plurality of dependent stations that are connected by two up and down transmission lines to form a ring, and are placed at predetermined positions within the ring to monitor and control each of the dependent stations and detect an abnormality; In a ring-type local area network that includes a management station that sends a loopback command to a dependent station whose input signal has been cut off, and also performs loopback processing itself to reconfigure a new ring, It is placed at a predetermined position within the ring and is separately connected to the management station via a dedicated line, and is in a through state during normal times.When the management station detects an abnormality, the information is sent from the management station via the dedicated line. The standby management station cancels the through state according to the instructions received, sends a loopback command to the dependent station whose input signal has been cut off, and also performs loopback processing itself to reconfigure a new ring. A ring-type local area network characterized by the provision of. (2) A plurality of dependent stations that are connected by two up and down transmission lines to form a ring, and are placed at predetermined positions within the ring to monitor and control each of the dependent stations and detect an abnormality; In a ring-type local area network that includes a management station that sends a loopback command to a dependent station whose input signal has been cut off, and also performs loopback processing itself to reconfigure a new ring, It is placed at a predetermined position within the ring, and is in a through state during normal operation, and releases the through state when an abnormality occurs, sends a loopback command to the dependent station whose input signal is cut off, and also loops itself. A standby management station that performs backup processing and reconfigures a new ring, and a standby management station that is inserted into a predetermined transmission path within the ring and connected to each other by a detour path, and is in a through state during normal conditions, and the through state when an abnormality occurs. A ring-type local device comprising: a failure detour device that cancels the state and forms a failure detour route that connects the newly reconfigured ring between the management station and the standby management station via the detour route. area network.