JP2544301B2 - Method and concentrator for avoiding transmission line failure in hierarchical network - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an Ethernet 10BA.
The present invention relates to a system such as SE-T that enables network operation by automatically switching lines when a failure occurs such as disconnection / mixing of transmission lines in a local area network in which concentrators are arranged in a hierarchy. , To be more specific, even in a network in which transmission data from the lower layer to the upper layer is not returned to the same route, even if a failure occurs only in the transmission path from the upper layer to the lower layer, The present invention relates to a method and a concentrator for avoiding a transmission line failure in a hierarchical network that enables operation of a network even when a failure occurs only in a transmission path to an upper layer or in both cases. .

[0002]

2. Description of the Related Art Conventionally, there has been a backup technology for a local area network that uses a double loop type topology. By the way, in a hierarchical local area network using a concentrator, each communication port of the communication station and the concentrator is connected one-to-one, so that there is a failure in the transmission line between the communication station and the concentrator. There is an advantage that it does not affect the communication of the communication station.

[0003]

However, in the hierarchical type, when a failure such as a disconnection or a cross line occurs in the transmission line between the upper layer concentrator and the lower layer concentrator, the lower layer concentrator is connected to the lower layer concentrator. The existing communication station is blocked from communication by the point of failure and cannot communicate with other communication stations, resulting in widespread damage of the failure.

Japanese Patent Application No. 2-92132 discloses a concentrator for avoiding a transmission path failure in a host-dependent star-type network. This concentrator can select one transmission path to be used from the two transmission paths, and the selection of the transmission path is performed by transmitting the transmission data from the lower layer to the upper layer and returning the two transmission paths. This is a configuration performed by comparing with data.

That is, in the host-dependent star network, the transmission data from the lower layer to the upper layer is the same as the loopback data of the two transmission paths when no failure occurs, and they differ when a failure occurs. Therefore, by providing such a concentrator, it becomes possible to avoid a failure of the transmission line and perform normal communication.

However, in the hierarchical network such as Ethernet 10BASE-T, which is not the mainstream host-dependent system currently used, that is, the transmission data from the lower layer to the upper layer is not returned to the same route, the concentrator is always used. There is a problem that it cannot be applied because it is the same as when a failure occurs.

An object of the present invention is to solve this problem. By automatically switching lines when a failure occurs such as disconnection or cross-linking of a transmission line of a network in which concentrators are arranged in a hierarchy. In order to enable the operation of, even in the network of the method in which the transmission data from the lower layer to the upper layer is not returned to the same route, even if a failure occurs only in the transmission path from the upper layer to the lower layer, A method for avoiding a transmission line failure in a hierarchical network that enables network operation even if a failure occurs only in the transmission path from the lower layer to the upper layer, or in both cases. And a line concentrator.

[0008]

Means of the present invention taken to solve the above problems are as follows. According to the first aspect of the present invention, in the concentrator arranged in a hierarchical network, the lower communication port of the concentrator of the upper layer is connected to the upper communication port of the concentrator of the lower layer and is in the same layer. The concentrator has a transmission line configured by connecting a spare upper communication port and a spare lower communication port, respectively, and detects a fault when a signal cannot be received, and a fault in the upper receiving port. In this case, the backup upper communication port is set to the upper side, and the step of transmitting only a signal for connection confirmation to the upper communication port that has detected the failure, and the case where the failure is detected in the lower receiving port, And the step of stopping transmitting a signal to the lower transmission port that has detected a failure, even if the transmission data from the lower layer to the upper layer is not returned to the same route. Characterized in that to enable operation of the click is a way to avoid the transmission line fault of the hierarchical network.

According to a second aspect of the present invention, there is provided a concentrator capable of avoiding a transmission line failure of a hierarchical network, the concentrator having an upper communication port, a lower communication port,
An upper communication port for backup, a lower communication port for backup, and a connection branch circuit, wherein the upper communication port is an upper reception port equipped with an abnormality detection circuit, a connection confirmation signal addition circuit, and a signal cut circuit. Upper side transmission port equipped with
Wherein the lower communication port comprises a lower reception port having a connection confirmation signal deletion circuit and an abnormality detection circuit, and a lower transmission port having a signal cut circuit, and the backup higher communication port. Includes a backup upper reception port and a backup higher transmission port including a signal cut circuit, and the backup lower communication port includes a backup lower reception port and a backup lower transmission port, A selection circuit is provided between the backup upper reception port and the upper reception port to enable operation of the network even when transmission data from the lower layer to the upper layer is not returned to the same route. It is a concentrator used in a hierarchical network.

The lower-side transmission port is provided with a signal cut circuit, and by cutting the signal to the lower layer, the concentrator connected to the lower side does not receive a signal from the concentrator of the upper layer, so that a failure is detected. can do. This makes it possible to avoid a failure in the transmission path from the lower layer to the upper layer. In other words, in order to create the same condition as when a failure in the transmission path from the lower layer to the upper layer is forced to occur in the upper layer, a failure in the transmission path from the upper layer to the lower layer, Is equipped with a signal cut circuit.

The connection confirmation signal addition circuit and the connection confirmation signal deletion circuit are for detecting a failure, and the connection confirmation signal is used to check whether or not the other party is connected.
If the other party is not connected, there will be no signal, so in that case we try to regard it as a failure.

Since the connection confirmation signal needs to exist only between the concentrator and the communication device that are directly connected to each other, the concentrator needs a function of deleting or adding the signal.
Also, in a hierarchical network, normally, the signal for the original communication is not always transmitted from the lower layer to the upper layer. Therefore, such a confirmation signal is necessary, but from the upper layer to the lower layer. There is also a system in which the original communication signal is always transmitted. In that case, since it can be considered that there is no failure if the original communication signal comes, it is simply an abnormality detection circuit.

The signal cut circuit of the upper transmission port and the signal cut circuit of the backup upper transmission port have the function of invalidating one of them in order to unify the signals to be sent to the upper layer. Whether to invalidate is determined by the selection circuit. This is because if both signals are always valid, the same signal will be transmitted to the upper layer by the routes of the two systems, and eventually the same signal will collide with each other and correct transmission cannot be performed.

The selection circuit causes the spare upper communication port to perform transmission / reception normally performed by the upper communication port when a failure occurs. The signal cut circuit of the upper transmission port and the spare upper transmission port are used. At the same time as turning on / off the signal cut circuit of the port, the receiving port is switched from the normal upper port to the standby upper port.

By alternately connecting the spare upper communication port and the spare lower communication port of the concentrator located in the same layer among the concentrators having the above-mentioned configurations, in the case of a failure such as a disconnection or cross-linking of the transmission line. Configure a communication path that bypasses the point of failure.

Particularly, in the concentrator according to the present invention, since the connection confirmation signal adding circuit is provided in the upper transmission port and the connection signal deletion circuit and the abnormality detection circuit are provided in the lower reception port, the configuration is adopted. It is possible to detect that a failure has occurred in the transmission path from the lower layer to the upper layer. That is,
Since the signal cut circuit of the lower transmission port does not send the signal to the lower layer, the same state as when a failure occurs in the transmission path from the upper layer to the lower layer occurs. Even when a failure such as disconnection or crossing occurs only on the road, it becomes possible to automatically switch the lines and continuously operate the network.

By providing a means for transmitting fault detection data indicating which port detects a fault in the concentrator to the monitoring device, the monitoring device can notify the fault occurrence warning and the fault occurrence route. .

[0018]

The present invention will be described in more detail based on the embodiments shown in the drawings. FIG. 1 is an explanatory diagram showing an embodiment of a transmission line formed by connecting concentrators used in a hierarchical network. The transmission line 1 includes one upper layer concentrator 101 and three lower layer concentrators 102, 103, 1
Has 04.

Concentrators 101, 102, 103, 104
Have the same structure and are provided with an upper communication port 10, a lower communication port 11, a spare upper communication port 12 and a spare lower communication port 13, respectively. These line concentrators are arranged in a hierarchical manner and the transmission paths 110, 111, 112, 11 are arranged.
3, 114, 115 are connected to form a network.

FIG. 2 is a block diagram showing the structure of the line concentrator shown in FIG. The configuration of the concentrator will be described with reference to FIG. The spare upper communication port 12 includes a spare upper receiving port 201 and a spare upper transmitting port 202 including a signal cut circuit 224. Signal cut circuit 2
24 cuts the transmission by the action of the inverter 222 except when a failure is detected. The backup lower communication port 13 includes a backup lower transmission port 203 and a backup lower reception port 204.

The upper communication port 10 has an abnormality detection circuit 2
An upper side reception port 205 provided with 23 and a higher side transmission port 206 provided with a connection confirmation signal addition circuit 207 and a signal cut circuit 208 are provided. Lower communication port 11
Is a lower-side reception port 218 including connection confirmation signal deletion circuits 211 and 212 and abnormality detection circuits 214 and 216.
220, and lower transmission ports 217 and 219 provided with signal cut circuits 213 and 215.

The signal cut circuits 208, 213 and 215 cut the transmission when a failure is detected. The selection circuit 2 is provided between the spare upper reception port 201 and the upper reception port 205.
09 is provided. The selection circuit 209 is for using the signal from the spare upper reception port 201 instead of the signal from the higher reception port 205 when a failure is detected. The connection branch circuit 210 branches the signal from the upper layer to the lower layer and connects the signal from the lower layer to the upper layer. The above ports and circuits are connected as shown.

As described above, the connection branch circuit 210 branches a signal from the upper communication port 10 to the lower communication port 11, and connects only valid data from the lower communication port 11 to the upper communication port 10. It is for morphology.
In 10BASE-T, this connection branch circuit 210 is in the form of a bus. In this figure, the lower communication port 11 is 1
There are two numbers, n and n, but it can be any number.

The concentrator has an abnormality detection circuit 223 for detecting a transmission line fault. The signal received by the upper reception port 205 is sent to the abnormality detection circuit 223. When the abnormality detection circuit 223 does not detect a transmission path fault, it is transmitted to the connection branch circuit 210 via the selection circuit 209. When the abnormality detection circuit 223 detects a transmission path failure, the signal received by the spare upper reception port 201 by the selection circuit 209 is transmitted to the connection branch circuit 210.

The signals received by the lower-order receiving ports 218 and 220 are transmitted to the abnormality detecting circuits 214 and 216, respectively. Also, the connection confirmation signal deletion circuits 211 and 21
After deleting the connection confirmation signal in 2, the connection branch circuit 210
Is transmitted to The signal received at the backup lower reception port 204 is directly transmitted to the connection branch circuit 210.

From the connection branch circuit 210, a signal is directly transmitted to the backup upper transmission port 202 through the signal cut circuit 221 and to the backup lower transmission port 203. It is transmitted to the lower transmission ports 217 and 219 via the signal cut circuits 213 and 215.

The signal cut circuits 213 and 215 do not transmit the signal from the connection branch circuit 210 to the port when the abnormality detection circuit 223 detects a failure in the transmission path from the upper layer to the lower layer. Further, the signal cut circuit 224 transmits a signal to the spare upper transmission port 202 when the abnormality detection circuit 223 detects a higher level transmission path failure.

(Operation) As shown in FIG. 1, the concentrator shown in FIG.
By connecting with 0, 111, 112, 113, 114, 115, it becomes possible to back up against a failure in the transmission path.

That is, the upper layer concentrator 10 shown in FIG.
1 lower communication port 11 to lower layer concentrator 102
Transmission path 110 for transmitting a signal to the upper communication port 10 of
If a failure such as disconnection / mixing occurs in the line, the concentrator 10
2 is from the backup lower communication port 13 of the concentrator 103,
A signal transmitted to its own spare upper communication port 12 via the transmission path 113 can be regarded as a signal from the upper layer concentrator 101 side and can be transmitted to the lower communication port 11.

The signal transmitted from the upper-side communication port 10 of the lower-layer concentrator 102 to the lower-side communication port 11 of the upper-layer concentrator 101 during normal operation is used as a backup signal for the concentrator 103 of the same layer when a failure occurs. The signal is transmitted to the lower communication port 13, and only the connection confirmation signal is transmitted from the upper communication port 10 of the concentrator 102 to the lower communication port 11 of the concentrator 101.

Since the signal for confirming the connection is not transmitted to other devices, the route transmitted to the upper layer of the concentrator 102 is the backup upper communication port 12 of the concentrator 102 and the backup lower communication of the concentrator 103. Only the signals are transmitted to the concentrator 101 through the port 13, and no signal collision occurs.

If a signal for connection confirmation is started to be received from the upper communication port 10 of the concentrator 102 after the failure is detected, it can be considered that the failure has been removed and the recovery has been completed. Therefore, it is possible to return to the normal transmission path 110.

When a failure occurs in the path for transmitting a signal from the upper communication port 10 of the concentrator 102 of FIG. 1 to the lower communication port 11 of the concentrator 101, the lower communication of the concentrator 101 that has detected the failure. The port 11 stops transmitting signals, and the upper communication port 10 of the concentrator 102
Can detect the occurrence of a failure and establish a signal transmission path by the same operation as when a failure occurs in the path for transmitting a signal from the lower communication port 11 of the concentrator 101 to the upper communication port 10 of the concentrator 102. To construct.

With the above configuration, the network can be operated even when a failure occurs. In addition, since the network can be operated when a failure occurs, the information that the concentrator has detected a failure can be transmitted to other devices through the network. Centralized control of the generation route becomes possible. The present invention is not limited to the illustrated embodiments, and various modifications can be made within the scope of the claims.

[0035]

As is clear from the above description, according to the present invention, regardless of whether or not the transmission data from the lower layer to the upper layer is returned to the same route, in the transmission path of the hierarchical network, Even if a failure occurs only in the transmission path from the upper layer to the lower layer, a failure occurs only in the transmission path from the lower layer to the upper layer, or when both of them occur, Lines can be switched to avoid transmission line failures. Therefore Ethernet 1
Even when a failure such as disconnection or cross-linking of a transmission line of a local area network in which concentrators are arranged hierarchically is used, such as 0BASE-T, in which transmission data from a lower layer to an upper layer is not returned to the same route. Network operation becomes possible. In addition, since it is possible to centralize fault monitoring by providing a means for transmitting fault detection data to a monitoring device, it is used for network systems in which the time from the occurrence of faults such as disconnection / mixed lines to restoration is a problem. It is effective in some cases.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a transmission line formed by connecting concentrators used in a hierarchical network.

FIG. 2 is a block diagram showing a configuration of a line concentrator.

[Explanation of symbols]

 101, 102, 103, 104 Concentrator 10 Upper communication port 11 Lower communication port 12 Backup upper communication port 13 Backup lower communication port 210 Connection branch circuit 214, 216, 223 Abnormality detection circuit 205 Upper reception port 207 Connection Confirmation signal addition circuit 208, 213, 215, 224 Signal cut circuit 206 Upper transmission port 211, 212 Connection confirmation signal deletion circuit 218, 220 Lower reception port 217, 219 Lower transmission port 201 Spare upper reception port 202 Spare Upper transmission port 204 Backup lower reception port 203 Backup lower transmission port 209 Selection circuit

Claims (2)

(57) [Claims] 1. The concentrator is configured in a hierarchical network.
The lower side communication port of the upper layer concentrator is
Connected to the upper communication port of the lower layer concentrator,
The concentrators in each layer are the backup upper communication port and the
The lower communication port for equipment is connected and the transmission line is configured.
The fault detection step that detects a fault when no signal is received.
When a failure is detected in
The communication port is set as the upper side, and the upper side communication that detected the above failure is
Step to send only connection confirmation signal to the communication port
When a fault is detected in the lower receiving port,
The status that the signal is no longer transmitted to the detected lower transmission port.
Tsu includes a flop, the transmission data is the same route from the lower layer to the upper layer
Enables network operation even if it is not returned to
A method for avoiding transmission line failure in a hierarchical network characterized by
Law. 2. Avoiding a transmission line failure in a hierarchical network
A concentrator that is capable of providing an upper communication port, a lower communication port, a backup upper communication port, a backup lower communication port, and a connection branch circuit. The port includes an upper-side reception port equipped with an abnormality detection circuit and an upper-side transmission port equipped with a connection confirmation signal addition circuit and a signal cut circuit.The lower-side communication port is a connection confirmation signal deletion circuit. A lower-order reception port equipped with an abnormality detection circuit and a lower-order transmission port equipped with a signal cut circuit, and the above-mentioned higher-order communication port for protection, a higher-order reception port for protection, and a higher-order protection device equipped with a signal-cut circuit. The backup lower communication port includes a backup lower reception port and a backup lower transmission port, and the backup higher reception port and higher reception Between the over preparative includes a selection circuit, the transmission data of the lower layer to the upper layer
Network is not returned to the same route.
A concentrator used in a hierarchical network, which is characterized by enabling the operation of the network.