JPH03206753A - Transmission line connection system in local area network - Google Patents

Abstract

PURPOSE:To improve the reliability of a local area network equipment by providing a repeater unit to reconnect a transmission line between branch transmission lines. CONSTITUTION:Repeater units 6a, 6b, 6c for reconnection of transmission lines are provided between branch transmission lines 4b and 4c, 4d and 4g, and 4f and 4h. They are not connected when bridge units 1a-1g are operated normally, and when the bridge units are out of order, the relay function of the repeater units 6a, 6b, 6c is made active and a faulty branch transmission line is reconnected to other branch transmission line to continue the connection to a trunk transmission line via normal bridge units. Thus, it is prevented that branch transmission lines are made isolated from the trunk transmission line due to a fault of the trunk transmission line or a fault of the bridge units 1a-1g.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a transmission line connection system in a local area network system having a hierarchical structure consisting of a main transmission line and a branch transmission line.

[Conventional technology]

Conventionally, this type of network device has been configured as shown in FIG. 5, for example, in which la, i b, .
．． ．． ．． ．．・, If, etc. are bridge units BU, 2 a, 2 that connect the main transmission line and the branch transmission line and transmit and receive signals to be relayed between the branch transmission line and the main transmission line.
b・---・---. 2 f etc. and 3a, . −． ．． ．． ．． ，
3f etc. are ring-type trunk transmission lines, 4a, 4b, .
．． ．． ．． ．． ．． , 4 r etc. are C S M A / C D
(CarrierSense Multiple Ac
cess/Collision Detection)
This is a bus-type branch line transmission line based on the system. Also 5a1,5
a2. ．． ．． ．． ..., 5f2, etc. are terminal devices T, which are connected to the branch transmission lines 4a to 4f, respectively.

Signals are exchanged between terminal devices T, and the transmission and reception within the branch transmission line is directly between the terminal devices T, and the signal transmission and reception between terminal devices T connected to different branch transmission lines is via a bridge connected to the main transmission line. This is done via unit BU. The bridge unit here refers to the International Organization for Standardization (ISO) OSI (Open System
The repeater unit interconnects two networks by converting the physical layer and data ring layer of the seven-layer reference model shown in s Interconnection, and the repeater unit performs interconnection at the physical layer.

[Problem to be solved by the invention]

Conventional local area network devices of this type are configured as described above, so if one bridge unit fails or the main transmission line fails, signals cannot be sent and received between the bridge unit and the main transmission line. If this becomes impossible, there is a problem in that terminal devices connected to a branch transmission line connected to the bridge unit cannot communicate with terminal devices connected to other branch transmission lines via the main transmission line.

For example, in FIG. 6 showing a conventional local area network of this type, 7a and 7b are trunk transmission lines 2.
a. 3a. 2b and -3b are shown, and the other numbers are the same as those shown in FIG. In response to a fault in a main transmission line at one location, the transmission line is duplicated and the signal transmission directions are set in opposite directions to each other, and in the event of a fault, the relevant fault section is avoided by a method called a lube bathock. However, in Fig. 6, the main transmission line 2a
．． 3a. If two failures occur in 2b and 3b, such as 7a and 7b, the bridge unit 1b will be unable to communicate with the main transmission lines 2a, 3a, 2b, and 3b, so the branch transmission line connected to them will not be able to communicate. Terminal device 5bl.4b connected to terminal device 5bl. 5b2 becomes unable to communicate with a terminal device connected to a branch transmission line other than the transmission line to which it itself is connected.

Further, the same applies when the bridge unit lb itself breaks down.

By the way, the control method of the junction box in the ring-type network shown in Japanese Patent Application Laid-open No. 61-33049 for reference is based on the main ring (corresponding to the main transmission line of the present invention) and the sub-ring (corresponding to the branch transmission line of the present invention). ), the key point is considered to be to separate the sub-ring from the main ring when there is a failure in the sub-ring, or to incorporate the sub-ring into the main ring. However, the purpose of the present invention is to prevent the branch transmission line from becoming isolated from the main transmission line due to a failure in the main transmission line or a failure in the bridge unit (corresponding to the junction box in the publication), and to prevent the branch transmission line from becoming isolated from the main transmission line due to failure of the main transmission line or failure of the bridge unit (corresponding to the junction box in the publication). Sometimes isolated branch transmission lines are connected to non-isolated branch transmission lines. This point of view is different from the prior art disclosed in the publication.

Further, in the network disclosed in the publication, the main ring and sub-ring do not operate independently. In the present invention, the branch transmission line can operate independently even if the main transmission line does not operate, but as mentioned above, it is possible to prevent the branch transmission line from becoming isolated from the main transmission line due to inability to perform relay operation. is aiming for.

This invention was made in order to solve the above-mentioned problems, and when a certain bridge unit becomes unable to communicate with the main transmission line due to a fault in the main transmission line, or when the bridge unit itself has a fault. Even if the relay function with the main transmission line is lost, the branch transmission line connected to the bridge unit can be reconnected to the branch transmission line connected to another bridge unit, allowing communication between terminal devices to continue. The purpose of this paper is to provide a transmission path connection method for area network equipment.

[Means for Solving the Problems] The transmission line connection system according to the present invention connects the branch transmission lines 4b and 4.
Repeater units 6a, 6b, 6C are connected between 0, 4d and 4g, and 4f and 4h for connecting the transmission line,
Bridge unit la, lb. lc, ld, le, If
．． When Ig is operating normally, repeater unit 6
Two branch transmission lines 4b and 4 connected by a, 6b, 6c
0, 4d and 4g, 4f and 4h are not connected, and Brisojunisoto la, lb, lc. ld, le, if. 1g itself or the bridge unit la, lb. lc
,ld,le. If. Ig and trunk transmission lines 2a, 2b,
2c. 2d, 2e, 2f, 2g, 3a. 3b
, 3c. 3d. When a connection failure occurs between 3e, 3f, and 3g, enable the relay function of the corresponding Revita UniSoto, connect the corresponding branch line transmission line to another branch line transmission line, and connect it to the main transmission line via a normal bridge unit. The feature is that the connection continues.

[Effect]

For example, if a failure occurs in the presoji unit lb itself, or if a failure occurs between the bridge unit 1b and the main transmission lines 2b, 3
If a connection failure occurs between the repeater
6a reconnects the branch transmission line 4b to another branch transmission line 4C. As a result, the connection from the main transmission lines 2a, 3a to the main transmission lines 2c, 3c is continued via the normal bridge unit 1C.

〔Example〕

FIG. 1 is a block diagram showing the structure of a local area networking device employing a transmission line connection system according to an embodiment of the present invention. In FIG. 1, components corresponding to those shown in FIG. 5 are given the same reference numerals. In Fig. 1, la,..., le, etc. are prinji units, 2a,..., 2h, etc. and 3a,...
, 3h, etc. are main transmission lines, 4a, . ．． ．． ．． ．． , 4h, etc. are branch transmission lines, 5a1, . . . , 5h2, etc. are terminal devices, and 6a, . . . , 6c, etc. are repeater units. In order to explain further details as an embodiment of the present invention, the structure of the bridge unit BU is shown in FIG.
FIG. 3 shows the structure of repeater unit RU. In FIG. 2, ○Tl and ○T2 are signal transmission circuits to the main transmission line 2, and since a high transmission speed is required, circuits that convert electrical signals into optical signals are used. ORI,○R
2 is a signal receiving circuit from the main transmission line 3, which converts an optical signal into an electrical signal. CTI is a transmission circuit that transmits the relay signal from the main transmission line 2.3 to the branch transmission line 4, CT2 is a transmission circuit that transmits a relay suppression signal that suppresses the relay function of the repeater unit, and CR is the transmission circuit that transmits the relay signal from the branch transmission line 4. This is a receiving circuit that receives signals. Relay control circuit RC is transmitter circuit O
TI, OT2. CTI and receiving circuits ORI, OR2,
This control circuit is located between the received signals from the CR and relays the signals on the branch transmission line 4 and the signals on the main transmission lines 2 and 3.

ERRD is a fault detection circuit that detects a fault in the prinzi unit itself, HDETI. HDET2 is a survival confirmation signal detection circuit, SUP is a relay suppression signal generation circuit, CCI is a circuit for transmitting circuits CTI and CT2 to prevent the signals from returning to the receiving circuit CR, and receiving signals from the branch transmission line 4 to be received by the receiving circuit ○R1. Alternatively, it is a receiving circuit, a circulator circuit that allows mOR2 to receive the signal.

The revitator unisoto RU shown in FIG. 3 is a device that can connect branch transmission lines 4 and relay signals.
T2 is a transmitting circuit that transmits a signal to the branch line transmission line 4 using, for example, a coaxial cable, Rl and R2 are receiving circuits that receive signals from the branch line transmission line 4, and CC2. CC3 is the transmitting circuit TI
, T2 is a circulator circuit that prevents the signal from returning to the receiving circuit CR from being received, and allows the received signal from the branch transmission line 4 to be received by the receiving circuit R1 or R2. DETI and DET2 detect the relay suppression signal. This is a relay suppression signal detection circuit. SWC is a switch SW for a predetermined period of time when either the relay suppression signal detection circuit DETI or DET2 detects the relay suppression signal.
I. This is a switch control circuit that turns off SW2 and turns off the switch SWI and SW2 when the relay suppression signal is not received within the predetermined time.

Figure 4 shows a case where a failure occurs in the trunk transmission line or a failure in the bridge unit in a network device having the structure shown in Figure 1, and 7a and 7b in the figure indicate failures in the trunk transmission line. The 10 x marks indicate a failure in the bridge unit itself. Other numbers are shown in Figures 1 and 2.
figure. It is equivalent to Figure 3.

Next, the operation of this embodiment will be explained in detail using FIG. 1, FIG. 2, FIG. 3, and FIG. 4. If a fault occurs in both the trunk transmission lines 2a, 3a or 2b, 3b in FIG. 1, or if a fault occurs in the bridge unit 1b, as shown in FIG. Therefore, the terminal devices 5bl and 5b2 connected to the branch transmission line 4b are unable to communicate with terminal devices connected to other branch transmission lines via the main transmission line. It becomes impossible.

The bridge unit 1a with the management function shown in FIG. 1 periodically transmits a survival confirmation signal, and the other bridge units receive the survival confirmation signal. In the bridge unit BU of FIG. 2, the survival confirmation signal is received by the receiving circuit ORI or the receiving circuit OR2,
It is detected by the survival confirmation signal detection circuit HDETI or the survival confirmation signal detection circuit HDET2. When this survival confirmation signal is received, the relay suppression signal generation circuit sup generates a relay suppression signal and sends it to the branch transmission line 4 via the transmission circuit CTI. This relay suppression signal transmission is performed every time the survival confirmation signal is received. In addition, the failure detection circuit ERRD
When detecting a failure in the bridge unit BU, it stops transmitting the relay suppression signal to the branch transmission line 4 even if it has received the survival confirmation signal.

The repeater unit RU in FIG.
Both branch transmission lines 4 have transmitting circuits and receiving circuits, respectively.

Normally, this repeater unit RU receives signals from the two branch transmission lines 4, and the bridge unit 1b or the main transmission line 2a+3a or 2b,
In order to receive the relay suppression signal within a predetermined time if there is no fault in the relay control signal 3b, the so-called so-called signal that is received from one branch transmission line 4, that is, a signal other than the relay suppression signal, is transmitted to another branch transmission line. Relay function is suppressed. However, if the relay suppression signal is not received within a predetermined time, the revitator unit 7RU relays the signal received from one branch transmission line to another branch transmission line. Therefore, even if a failure occurs in one of the bridge units or the main transmission line and communication from the bridge unit to the main transmission line becomes impossible,
Since signals for communication from terminal devices connected to the branch transmission line are relayed to other bridge units via the repeater unit RU, communication with the main transmission line can be continued.

FIG. 4 shows a case where a failure occurs in the trunk transmission line or in the bridge unit in the network device having the configuration shown in FIG. At this time, the terminal device connected to the branch transmission line becomes unable to communicate with the terminal device connected to another branch transmission line. Furthermore, the repeater unit connects the branch transmission line to another branch transmission line to relay the signal, connects it to the main transmission line via another bridge unit, and resumes communication with the other party's terminal device. It is shown that. Also, in the above explanation, the repeater unit was explained as being connected to two branch transmission lines, but this is connected to three branch transmission lines.
In that case, the relay suppression signal is no longer received and the relay connection between the branch transmission line and the second or third branch transmission line is stopped. In this case, a predetermined branch transmission line or an arbitrary branch transmission line from among the second, third, . . . , Nth branch transmission lines that can receive at least the relay suppression signal. All you have to do is set up a relay function between them. In general, there is a high probability that only one bridge unit will fail, and a low probability that two or more bridge units will fail at the same time. Therefore, in the case of a failure of a bridge unit, in most cases it is sufficient to simply disconnect the branch line transmission line from the failed bridge unit and reconnect it to another bridge unit.

As explained above, in the above embodiment, when a failure occurs in a bridge unit, the corresponding branch transmission line is reconnected to a branch transmission line that connects to a normally operating bridge unit, thereby preventing communication to the main transmission line. This is an attempt to secure a road. For this purpose, a repeater unit is connected between the branch transmission lines for reconnection, and when Purinjunisoto is operating normally, the two branch transmission lines are not connected, and the bridge unit itself is not at fault. , or when a connection failure occurs between the bridge unit and the main transmission line, enable the relay function of the repeater unit, reconnect the branch line transmission line to another branch line transmission line, and connect the branch line to another branch line via the normal bridge unit. This allows the connection to the main transmission line to continue. The bridge unit has means for confirming that the connection with the main transmission line is operating normally, and based on the confirmation of normal operation, it issues a signal to suppress the relay function to the repeater unit, and the repeater unit performs the connection. If the relay function suppression signal from both branch transmission lines is not received from either branch transmission line for a certain period of time,
Data signal relay is performed.

Therefore, according to the above embodiment, the bridge unit and the repeater unit are used in the local area networking device to transmit the relay suppression signal upon reception of the survival confirmation signal, and the relay suppression signal is transmitted when the survival confirmation signal cannot be received or the bridge unit is In the event of a failure, the repeater unit is configured not to transmit the relay suppression signal, and if the repeater unit does not receive the relay suppression signal within a predetermined time, the relay function of the repeater unit is activated, Even if a failure occurs in a Brisojunisoto, communication via the main transmission line from the terminal device connected to the corresponding branch transmission line can be continued via other surviving Prisoji units. .

〔Effect of the invention〕

As described above, according to the present invention, a repeater unit for connecting transmission lines between branch transmission lines is provided. Connect 7 points,
When the bridge unit is operating normally, do not connect the two branch transmission lines connected by the repeater unit, and prevent a failure in the bridge unit itself or a connection failure between the bridge unit and the main transmission line. When this occurs, the relay function of the relevant revitator unit is enabled, the relevant branch line transmission line is reconnected to another branch line transmission line, and the connection to the main transmission line is continued through the normal presoji unit. If a bridge unit becomes unable to communicate with the main transmission line due to a fault in the main transmission line, or if the bridge unit itself fails and loses its relay function with the main transmission line, connection to the bridge unit will be made. It is now possible to continue communication between terminal devices by reconnecting the branch line transmission line that is connected to another branch line transmission line to another branch line transmission line that connects to another bridge. This has the effect that communication between the two can be carried out efficiently.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the structure of a local area networking device employing a transmission line connection system according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the structure of a bridge unit in this embodiment. Fig. 3 is a Bronnock diagram showing the structure of the repeater unit in this embodiment, and Fig. 4 shows a state in which a failure occurs in one bridge unit in this embodiment and it is relayed to another branch transmission line via a repeater unit. Figure 5 is a block diagram showing the structure of a conventional local area network system, and Figure 6 is a block diagram for explaining the structure of a conventional local area network system. FIG. 2 is a block diagram for explaining how a terminal device connected to a branch line transmission line connected to the bridge terminal becomes unable to communicate via the main line transmission line. la~le, BU...Blishninto, 2a
~2h, 3a~3h, 2.3... Main transmission line,
4a ~ 4h, 4... Branch transmission line, 5al ~
5h2. T...Terminal device, 6a to 6c. R.U.
...Repeater unit.

Claims (1)

[Claims] In a local area network device that is a hierarchical network consisting of a plurality of branch transmission lines connecting terminal devices and a main transmission line, and in which the main transmission line and the branch transmission line are connected by a bridge unit, there is a network between the branch transmission lines. A repeater unit is connected to connect the transmission line, and when the bridge unit is operating normally, the two branch transmission lines connected by the repeater unit are not connected, and there is a problem with the bridge unit itself, or When a connection failure occurs between the bridge unit and the main transmission line, the relay function of the corresponding repeater unit is enabled, the corresponding branch transmission line is connected to another branch transmission line, and the main transmission is resumed via the normal bridge unit. A transmission line connection method in a local area network device characterized by continuous connection to a transmission line.