JPH04200128A - Data exchange system and data exchange - Google Patents

Abstract

PURPOSE:To simplify the constitution of a node and to reduce the call time by allowing a logic communication line to select a physical trunk communication line regarded as a fault avoidance channel or the fault avoidance channel between subordinates node on the occurrence of a fault of the physical trunk communication line. CONSTITUTION:A physical trunk communication line is installed between a specific node and each subordinate node respectively and a fault avoidance channel is installed between plural subordinate nodes being logic nodes. When a fault takes place in one of the physical trunk communication lines being logic communication lines, a logic channel setting section of a specific node regards the physical trunk communication line connecting to other subordinate nodes being logic nodes together with subordinate nodes connecting to the physical trunk communication line having a fault as a fault avoidance channel of the physical trunk communication line having a fault and connects it to be used for the communication with the subordinate node connecting to the physical trunk communication line having a fault and connects the other subordinate nodes connecting to the physical trunk communication line disconnected from the fault avoidance channel and the fault avoidance channel between the subordinate nodes and the physical trunk communication line connecting to itself on its request.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a data exchange system and a data exchange device applied to, for example, a public telephone network, integrated service digital network (ISDN), etc. The present invention relates to a data exchange system and a data exchange device that can reliably and quickly avoid a failure when a failure such as a disconnection or short circuit occurs in a physical backbone communication channel connecting a subordinate node.

A conventional technical data exchange system includes a large number of terminal devices, a communication path and a switching device for connecting any two terminal devices among them independently from other terminal devices, and is also connected to a data communication network. Called.

The network configuration of a data exchange system can be roughly divided into a terminal switching method in which a switching device and a terminal device are directly connected on a one-to-one basis, and a center switching method in which a plurality of terminal devices are connected to one switching device.

In the case of the terminal switching method, a network communication path is required to connect each terminal and switching device to all other terminals and switching devices, so it is especially important to connect switching devices with a large amount of communication. From the viewpoint of increasing economic efficiency, it is not possible to install them over a wide area.

The center switching system has a so-called star-shaped network configuration, and is also called a relay switching system because the switching equipment relays communications between terminal devices. This center system requires the same number of communication paths as the number of terminals connected to the switching equipment. Therefore, if the geographical distance between the switching device and the terminal device is relatively short, or if the communication cost between the switching device and the terminal device is low, the network configuration will be highly economical. Connecting terminals distributed over such a wide area to a single switching device cannot be adopted from the viewpoint of improving economic efficiency.

Therefore, by developing the center switching system, multiple switching devices (nodes) connected to multiple terminals are connected in a star shape, net shape, honeycomb shape, or ring shape using trunk lines. It has been proposed that a large amount of data can be exchanged multiplexed between terminal devices. The network configuration of this type of data communication system that is actually installed is a network configuration that combines a star network configuration and a mesh network configuration to be most advantageous in reducing equipment costs and communication costs. has been adopted. When connecting exchange devices in a star pattern, the nodes have a hierarchy (hierarchy).
A hierarchical structure is adopted.

For example, as shown in Figure 5, NTT has established four levels of nodes: a central station RC, a central station DC, a central station TC, and an end station EO. A net-shaped network configuration is adopted between the central stations RC, and a star-shaped network configuration is adopted between the upper station and subordinate stations, and between the terminal station EO and the terminal device. are doing.

The intermediate wE line connecting the relay line to the upper station of band restriction and the general station is called a core circuit (core communication path), and the relay line provided between other switching devices is called a diagonal line.

After detecting that a certain route between the calling party and the called party is cold, this conventional switching equipment puts the call on hold and searches for another available route, and then sends the caller through that available route. is configured to transmit the call to the called party.

Problems to be Solved by the Invention In such a data exchange system, it is possible to select multiple routes from the calling party to the called party, and to connect the calling party to the called party more reliably. However, this requires that each switching device understand the entire network configuration and is also equipped with a complex algorithm for routing, making the configuration of each node extremely complex. There is a problem with becoming.

Furthermore, since routing operations are performed for each switching device intervening on the route from the calling party to the called party, there is also the problem that the time required to call the called party and the time required to switch routes during communication become long.

Furthermore, if a failure occurs in a communication channel while exchanging highly real-time data such as moving images and audio, a problem arises in that the moving images and audio are interrupted while the communication channel is switched.

Therefore, in order to simplify the configuration of the node and shorten the call time or communication route switching time, the present inventor connected the specific node and subordinate node with two physical backbone communication channels each, and usually uses any one of the physical backbone communication channels as a normal physical backbone communication path, and monitors the communication status of the physical backbone communication path for specific nodes and subordinate nodes, and detects failures in the normal physical backbone communication path. When this occurs, it is conceivable to provide a data exchange device that switches the connection to a backup physical backbone communication channel and secures the connection between the dependent node and the specific node.

According to this idea, each node should be equipped with a switching device that monitors the communication status of the normally used physical backbone communication channel and switches the connection to another physical backbone communication channel when a failure occurs. The configuration of each node is much simpler compared to the case where each node grasps the entire data communication system and stores the algorithm for routing. Furthermore, since the time-consuming process of routing is not required for each note existing on the route between the calling party and the called party, it is also possible to shorten the calling time and the time for switching routes during communication.

However, according to this idea, there is a problem in that the number of communication paths connecting the specific node and the dependent node' is doubled, which increases the cost of communication equipment. In particular, considering that expensive communication lines capable of long-distance, high-speed, and high-density transmission are used as the physical backbone communication channels, it turns out that it is extremely difficult to implement this idea.

Next, the inventor focused on the fact that the physical backbone communication channel becomes unusable due to a fault in a relatively short period of time from the occurrence of the fault until it is repaired. and a fault avoidance communication path consisting of an inexpensive auxiliary communication line suitable for shorter distances, lower speeds, and lower density transmission. If no fault has occurred in the communication channel, the subordinate node and the specific node are connected via the physical backbone communication channel, and when a fault occurs in the physical backbone communication channel, the connection is switched to fault avoidance communication, It is conceivable to provide a data exchange device that secures a connection between the dependent node and the specific node via a failure avoidance communication path.

According to this idea, the configuration of each node becomes simple, similar to the case where two physical backbone communication channels, one for normal use and one for failure avoidance, are installed between a specific node and a dependent node, respectively.
Furthermore, the calling time and the time for switching routes during communication can be reduced to some extent.

However, in this idea, the conventional switching equipment starts searching for a communication path to use as a failure avoidance communication path after detecting that the physical backbone communication path is completely unusable.
After this, the configuration is configured to select a communication path to be used as a failure avoidance communication path and then switch to the failure avoidance communication path. Therefore, failure avoidance communication is performed after the physical backbone communication path becomes unusable. It is necessary to accumulate data sent from other terminals to subordinate nodes via the failed physical backbone communication path between the specific node and the specific node until the communication path is established. Even after this, the amount of data output from there to subordinate nodes via the failure avoidance communication path may be smaller than the amount of data input to the specific node, so a huge capacity buffer is installed on the specific node. This results in an increase in node equipment costs and running costs. In addition, it is necessary to provide a buffer with a considerably large capacity in subordinate nodes to accumulate data input during the time required to switch communication channels, which is disadvantageous in terms of reducing node equipment costs and running costs. .

The data exchange system according to the present invention has been developed in view of the above-mentioned circumstances, and is capable of reliably and rapidly connecting a specific node and its subordinate nodes when a failure occurs in the physical backbone communication channel. It is possible to connect a specific node and its dependent nodes while avoiding failures, simplify the configuration of each node, and use short-distance, low-speed,
An object of the present invention is to provide a data communication system and a data exchange device that can be connected using an inexpensive communication path suitable for low communication density transmission.

Further, the data exchange device according to the present invention is most suitable for application to the data exchange system of the present invention, and moreover, the data exchange device according to the present invention is suitable for application to the data exchange system of the present invention, and moreover, immediately before the physical backbone communication channel becomes completely unusable due to the occurrence of a failure, the communication path and the failure It is an object of the present invention to provide a data exchange device that can shorten the connection time during a failure avoidance operation by switching to an avoidance communication channel.

Means for Solving the Problems The data exchange system according to the present invention is based on a data exchange system in which a plurality of subordinate nodes are respectively connected to a specific node via physical backbone communication channels, and in order to achieve the above objects, The following measures have been taken:

That is, a failure avoidance communication path is laid between dependent nodes, and a plurality of dependent nodes connected to a specific node via the failure avoidance communication path are regarded as one logical node, and the specific node and each of the logical nodes constituting the logical node are A logical communication path setting unit is provided that forms a logical communication path in which each physical backbone communication channel connecting a subordinate node is regarded as a fault avoidance communication path for other physical backbone communication channels, monitors the communication status of the physical backbone communication path that connects the physical backbone communication path and the specific node, and if no failure has occurred in the physical backbone communication path, connects the subordinate node and the specific node only via the physical backbone communication path. , when a failure occurs in the physical backbone communication path, the connection is switched to the failure avoidance communication path, and the dependent node is connected to the failure avoidance communication path and other dependent nodes belonging to the same logical node, It is characterized in that it is provided with a data exchange device that connects to a specific node via a physical backbone communication channel that is regarded as a failure avoidance communication channel.

Further, a data exchange device according to the present invention includes a plurality of communication paths used for communication with a plurality of other nodes, and an exchange unit that selects a communication path to be operated from among the plurality of communication paths. To achieve the above purpose, assuming that
The following measures have been taken:

That is, a transmission status monitoring unit detects the transmission status of each communication channel, and a transmission status monitoring unit that detects the transmission status of each communication channel, and a transmission status monitoring unit that detects the transmission status of another communication channel when the occurrence status of a transmission failure on any communication channel among each communication channel is larger than a predetermined first specified value. a detour communication path selection unit that selects a communication path as a detour communication path and prepares the detour communication path for operation; The present invention is characterized in that it includes a detour communication path setting section that controls the exchange section to operate the detour communication path selected by the detour communication path selection section in place of the communication path that is currently in operation.

Function: In the data exchange system of the present invention, failure avoidance communication channels are laid between a plurality of subordinate nodes, each of which constitutes a logical node, with one physical backbone communication channel between each specific node and each subordinate node. .

In normal times, the communication path for avoiding obstacles is not used.
Each physical backbone communication channel acts as a normal physical backbone communication channel, and data exchange between each subordinate node and a specific node is
Each is performed via a physical backbone communication channel.

In addition, if a failure occurs in one of the physical backbone communication channels that constitute the logical communication path, the logical communication path setting section of the specific node will A dependent node connected to the physical backbone communication path where the fault occurred, considering the physical backbone communication path connected to the other subordinate nodes that constitute the node as a failure avoidance communication path for the faulty physical backbone communication channel. In addition to being connected to the physical backbone communication path that was used for communication with the subordinate node and which was no longer used as the failure avoidance communication path, this subordinate node also connected to the physical backbone communication path that was connected to itself according to its request. That is, the physical backbone communication path that is considered to be a failure avoidance communication path is connected to the failure avoidance communication path between subordinate nodes. Thereby, the specific node and the dependent node in which the failure has occurred are connected via the physical backbone communication path that is regarded as the failure avoidance communication path and the failure avoidance communication path between the dependent nodes.

In addition, in the dependent nodes connected to the physical backbone communication path where the fault has occurred, the data exchange device switches the connection from the physical backbone communication path where the fault has occurred to the fault avoidance communication path between the subordinate nodes, and also A transfer request is output to the subordinate node connected to the physical backbone communication channel that is considered to be the communication channel for use. In response to this request, dependent nodes connected to physical backbone communication paths that are considered to be communication paths for failure avoidance will Connect with the communication path.

As a result, the dependent node connected to the failed physical backbone communication path and the specific node are connected via the fault avoidance communication path between subordinate nodes F and the physical backbone communication path that is regarded as the fault avoidance communication path. That will happen. In this way, a specific node or subordinate node can simply switch from a normally used physical backbone communication path to a physical backbone communication path used as a failure avoidance communication path, or between dependent nodes for failure avoidance, without performing any routing operations. A communication circuit for failure avoidance is set up simply by switching the connection to the communication path.

Furthermore, dependent nodes interposed in the middle may simply perform a transfer operation and may not perform a routing operation.

Similarly, even if a failure occurs in the failure avoidance communication path during communication, a specific node or subordinate node simply uses the normally used physical backbone communication path as a failure avoidance communication path without performing any routing operation. It is only necessary to switch the connection to the physical core communication path or the failure avoidance communication path between subordinate nodes, and the intermediate dependent nodes only need to perform a transfer operation and do not need to perform a routing operation.

Therefore, there is no need to store data or algorithms necessary for the routing operation in the specific node and subordinate nodes. Furthermore, compared to conventional network configurations that involve routing operations, when a call is made or a failure occurs during communication, the connection time after the failure is detected is shortened, and the amount of time it takes to establish a connection (call costs) is reduced.

Furthermore, because of this, the amount of data accumulated while waiting for connection and transmitted from the calling terminal to the called terminal decreases.

In the data exchange device of the present invention, the transmission status of each connected communication path is detected by the transmission status monitoring unit, and the transmission failure occurrence status of any communication path among the communication paths is detected by a predetermined first If the detour communication path is larger than the specified value, the detour communication path selection unit selects another communication path as the detour communication path and prepares the detour communication path for operation. Then, when the transmission error occurrence state exceeds the first specified value and then exceeds the second specified value, the detour communication path setting unit controls the exchange unit to perform detour communication instead of the active communication path. The detour communication path selected by the path selection unit is activated.

Therefore, the detour communication path becomes operational at the same time as the communication path in operation is switched to the detour communication path, and time for switching the communication path becomes unnecessary.

Example Embodiments of the present invention will be described below based on the drawings.

In a data exchange system according to an embodiment of the present invention, for example, as shown in FIG.
2 to 15 are installed.

In addition, inter-dependent node communication paths 23 and 45 are set up between dependent nodes 2 and 3 and dependent nodes 4 and 5, which are geographically adjacent to each other or have low communication costs, and between dependent nodes 4 and 5, respectively, as communication paths for failure avoidance. has been done. Further, terminals 100 to 106 are connected to the specific node 1 and each subordinate node, respectively, and a logical communication path setting section 10 is attached to the specific node 1.

The logical communication path setting unit 10 selects geographically adjacent subordinate nodes 2 to 5 connected to the specific node 1, or subordinate nodes 2 to 5 with low communication costs. For example, a plurality of physical backbone communication channels 12 and 13 connecting logical node A and specific node 1 are grouped together and each is regarded as one logical node A-B. It is configured to form a logical communication path 20 that is regarded as an avoidance communication path.

More specifically, as shown in FIG. 3, for example, the logical communication path setting unit 10 only performs communication between a specific node 1 and one subordinate node 2 constituting the logical node A during normal operation. The physical backbone communication channel 12 that connects the
Only when a fault occurs in the physical backbone communication channel 12, another physical backbone communication channel 13 is used as a fault avoidance channel for the physical backbone communication channel 12.

In addition, between other subordinate nodes 3 and the specific node 1 within the same logical node A, the physical backbone communication path 13 that connects them is exclusively used as a normal physical backbone communication path during normal operation. The configuration is such that the connection destination of the specific node 1 is selected so that only when a failure occurs in the physical trunk communication path 13, another physical trunk communication path 12 is used as a failure avoidance communication path of the physical trunk communication path 13.

In addition, similarly to the above, this logical communication path setting unit 10 regards the other two subordinate nodes 4 and 5 as another logical node B, and each physical backbone connecting this logical node B and the specific node 1 The communication channels 14 and 15 are connected to other physical backbone communication channels 1.
4.15 is configured to form a logical communication path 21 which is regarded as a failure avoidance communication path.

Further, the logical communication path setting unit 10 configures the physical backbone communication paths 12 to
information indicating the correspondence between 15 and the logical communication paths 20 and 21;
That is, the physical backbone communication path 12 and the physical backbone communication path 13 constitute the logical communication path 20, and when a failure occurs in the physical backbone communication path 12, the physical backbone communication path 13 is used, and when a failure occurs in the physical backbone communication path 13, the physical backbone communication path 13 is used. When this occurs, physical backbone communication channel 1
2 or the information that physical backbone communication channel 1 is used.
4 and the physical backbone communication channel 15 constitute a logical communication channel 21,
When a failure occurs in the physical trunk communication channel 14, the physical trunk communication channel 15 is used, and when a failure occurs in the physical trunk communication channel 15, the information that the physical trunk communication channel 14 is used is sent to the corresponding subordinate nodes 2 to 5, respectively. configured to send to.

Physical trunk communication channel 1 output from the logical communication channel setting unit 10
Information 7 indicating the correspondence between 2 to 15 and the logical communication paths 20 and 21 is stored in the failure avoidance communication path setting unit 32 of each subordinate node 2 to 5.
~35.

Each failure avoidance communication channel setting unit 32 to 35 includes a physical backbone communication channel 12 that connects each dependent node 2 to 5 and the specific node 1.
~15 communication status is monitored, and the physical backbone communication channel 12~
If no failure has occurred in node 15, its subordinate nodes 2 to 15
5 and the specific node 1 exclusively through the physical backbone communication channels 12 to 15.
Data exchange devices 32 to 34 are provided to connect to the communication paths 23 and 45 for failure avoidance only when a failure occurs in the physical backbone communication paths 12 to 15.

In this data exchange system, when no failure occurs in each of the physical backbone communication channels 12 to 15, each subordinate node 2 to 5 independently connects to the physical backbone communication channels 12 to 15.
Each physical backbone communication channel 12 is connected to a specific node via
.about.15 will each function as a normal physical backbone communication channel.

Next, in this data exchange system, the operations of the communication route, logical communication path setting unit, and data exchange devices 32 to 35 when a failure occurs in the physical trunk communication channels 12 to 15 are explained below. An example of a case where this occurs will be explained.

In this case, the communication between the subordinate node 5 of the logical node B and the specific node 1 is considered to be a failure avoidance communication channel of the logical communication channel 21 and the physical trunk communication channel 14 and the subordinate node communication channel 4.
5.

That is, in the specific node 1, the logical communication path setting unit 10 operates the physical backbone communication path 14, which is considered to be a failure avoidance communication path, in place of the physical backbone communication path 15 in which the fault has occurred. A transfer request is output to the subordinate node 4 via the node. In response to this transfer request, the dependent node 4 connects the physical backbone communication path 14, which is considered to be a communication path for failure avoidance, and the inter-dependent node communication path 45. Furthermore, in the dependent node 5 connected to the physical backbone communication path 15 where the fault has occurred, the data exchange device 35 detects the fault in the physical backbone communication path 15, and connects the terminal 106 belonging to the dependent node 5 to the subordinate node communication path 45. Connect to.

In this way, the dependent node 5 and the specific node 1 are connected via the physical trunk communication path 14 and the inter-dependent node communication path 45, which are regarded as communication paths for failure avoidance.

Therefore, the specific node 5 and the dependent node 5 only switch the communication path from normal use to failure avoidance without performing any routing, and the intermediate dependent node 4 only makes a data transfer connection. , it is possible to shorten the time required from detection of a failure to completion of communication channel connection switching. Therefore, it is possible to use an inexpensive communication line that has lower communication speed, communication density, etc. than the physical backbone communication channels 12 to 15 as the communication line constituting the subordinate node communication path 45, thereby reducing communication costs. I can do it. Also, each subordinate node 2~
5 and the specific node for storing transmission data during the connection switching time can be reduced, and each of the dependent nodes 2 to 5 and the specific node 1 can be made smaller and less expensive. Furthermore, each subordinate node 2 to 5
Also, there is no need to store a routing algorithm in a specific node (the configuration of each node 1-5 can be made much simpler, each node 1-5 can be further downsized, and it can also be made cheaper. .

In the above embodiment, as the data exchange devices 32 to 35, conventionally known data exchange devices may be used, but for example, a data exchange device according to the present invention as shown in FIG. 2 may be used. By doing so, it is possible to virtually eliminate connection switching time when a failure occurs.

The data exchange device shown in FIG. 2 is connected to other notebooks via a plurality of communication paths 202 and 203 that are controlled independently of each other.

Here, since the data exchange device is provided in the subordinate nodes 2 to 5 that constitute the logical nodes A-B for the specific note river, one communication path 202 is connected to the physical trunk communication paths 12 to 15.
The other communication path 203 corresponds to the subordinate node communication path 2
Corresponds to 3.45.

The data exchange device includes communication control units 210 and 211 that individually control each communication path 202 and 203, an exchange switch 220 that selects the communication paths 202 and 203 and communication control units 210 and 211 to be activated, and Exchange switch control unit 221 that controls the switch 220, communication path 202.2
A traffic counting unit 230 for counting the traffic amount of data exchanged in 03, and communication paths 202 and 20.
a transmission/reception error counting unit 231 that counts transmission errors in 3;
a logical communication setting unit 232 that groups a plurality of communication paths 202 and 203 and sets one logical communication path; a first specified value setting unit 233 that specifies the number of transmission/reception errors for starting a detour communication path selection process; a first specified value comparison unit 235 for comparing the number of transmission/reception errors with a specified value;
A second regulation comparison unit 236 that compares the regulation value and the number of transmission/reception errors.
and a detour communication setting unit 238 that sets a communication path (here, 203) for detour communication.

Next, the operation of this data exchange device will be explained based on FIGS. 2 and 4.

The communication control units 210 and 211 control the transmission of the communication paths 202 and 203 connected to each other, and at the same time detect the amount of traffic on the communication paths 202 and 203. The communication control units 210 and 211 detect the number of transmission errors per unit time or per communication amount as transmission errors,
The detected transmission/reception errors are output to the transmission/reception error detection section 231 and counted for each communication control section 210/211. The number of transmission/reception errors occurring in the communication path 202 per unit time is compared with the setting value of the first regulation setting part 233 in the first regulation comparison part 235, and if is larger than the value set in the first regulation setting part 233, For example, a process for selecting a detour communication path for communication using a communication path 203 different from the communication path 202 currently in use is started. That is, the first specified value comparison section 235 compares the number of transmission and reception errors per unit time per communication path or per communication amount outputted from the transmission/reception error counting section 231 and the value set in the first specified value setting section 233. and if the number of transmission/reception errors is larger than the first specified value set by the first specified value setting unit 233, the detour communication path selection unit 237
A request signal for selecting a detour communication channel and an identification number of a communication channel whose number of transmission/reception errors is greater than a first specified value are output. If the number of transmission/reception errors is smaller than the first specified value set by the first specified value setting section 233, nothing is output to the detour communication selection section 237.

When the detour communication selection request signal is output from the first specified value comparison unit 235 to the detour communication selection unit 237, the detour communication selection unit 2
37 outputs to the logical communication setting unit 232 the identification number of the communication path in which the number of transmission/reception errors is greater than the first specified value, and the logical communication path setting unit 232 outputs the identification number of the communication path in which the number of transmission/reception errors is greater than the first specified value. Enter the identification numbers of all communication paths (here, only communication path 203) belonging to the same logical communication path as the number. The detour communication path setting unit 237 inputs the traffic amount for each communication channel identification number input from the logical communication path setting unit 233 from the traffic counting unit 230 as necessary, and selects the communication path or communication with the least traffic amount. The communication path with the largest margin of transmission capacity is determined as the detour communication path. That is, here, communication path 2, which is a backup communication path,
03 is determined as the detour communication path. Thereafter, when the number of transmission/reception errors per unit time or per number of communications becomes less than or equal to the first specified value, the selection of the detour communication path is canceled. However, the number of transmission and reception errors for each communication channel output from the transmission and reception error counting section 231 further increases, and the second
When the number of transmission/reception errors is greater than the second prescribed value set by the default value setting unit 234, the second prescribed value comparison unit 236 compares the second prescribed value when the number of transmission/reception errors is less than the second prescribed value set by the detour communication setting unit 238. The section 236 does not output anything to the detour communication setting section 238.

When the detour communication start request signal is output from the second specified value comparison unit 236 to the detour communication setting unit 238, the detour communication setting unit 238 transmits and receives the identification number of the detour communication channel 203 determined by the detour communication selection unit 237. Normal communication path 2 with many errors
02 identification number to the exchange switch control unit 221,
The exchange switch 220 actually changes the communication path to normal communication path 2.
02 to the backup detour communication path 203.

After that, when the normal communication channel 202 is restored and the number of transmission/reception errors per unit time or per number of communications decreases below the first specified value, the detour communication channel 203 is switched to the normal communication channel 202. It will be done.

In this embodiment, the second specified value is set to a value that has a high probability that the normal communication path 202 will become unusable. Switching from communication path 202 to communication path 203 will be performed.

In this way, in this data exchange system, when a failure occurs in the communication path 202 and there is a possibility that communication will be interrupted, the communication path 203 to be used as the detour communication path is selected,
Compared to the conventional data exchange system, which starts searching for a detour communication path 203 from the communication path 202 when there is a high probability that the communication path 202 will become unusable, not only can the connection switching time be shortened, but the occurrence of a failure can actually be avoided. It is also possible to eliminate the circuit switching time. Therefore, if this data exchange device is used as the data exchange device of the data exchange system according to the above embodiment, the physical backbone communication channels 12 to
This is optimal because it eliminates the time required to switch connections from the physical backbone communication paths 12 to 15 to the dependent node communication paths 23 and 45 when a failure occurs in the node No. 15, thereby reducing the − layer communication cost.

However, this data exchange system is based on the logical communication setting section 10 of the specific node 1 of the data exchange system of the above embodiment.
It can also be applied to

Effects of the Invention As described above, the data exchange system of the present invention allows logical communication to be performed without performing routing at a specific node, at a subordinate node, or at a subordinate node intervening in the middle for a detour when a failure occurs in a physical backbone communication channel. The communication path can be switched to a physical trunk communication path that is considered to be a failure avoidance communication path and a failure avoidance communication path between subordinate nodes.

Therefore, a signal transmission line can be used as a failure avoidance communication path between subordinate nodes, and the equipment cost of the entire data exchange system can be reduced.

Further, since there is no need to store a routing algorithm in the dependent node and the specific node, the configuration of the dependent node and the specific node can be made simple and inexpensive. 4. Furthermore, since the capacity of the second transmission during connection switching time can be reduced, subordinate nodes and special nodes can be made smaller and cheaper.

In particular, in the data exchange system of the present invention, when subordinate nodes that are geographically adjacent to each other or have low communication costs are regarded as logical nodes, the communication cost of the failure avoidance communication path between the subordinate nodes is reduced. This is advantageous because it can be made more inexpensively.

Further, according to the data exchange device of the present invention, if a failure occurs in one of the plurality of communication paths connected to a node,
Before the communication path becomes completely unusable due to the failure,
The communication path to be used for failure avoidance is selected from the remaining communication paths, and the connection is switched from the failed communication path to the failure avoidance communication path, so the time required to switch the connection to the failure avoidance communication path when a failure occurs is substantially reduced. As a data exchange device applied to the data exchange system of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration example of a data exchange device having a failure avoidance function of the present invention, FIG. 2 is a diagram showing a configuration example of a data exchange device having a failure avoidance function of the present invention, and FIG. FIG. 4 is a system configuration diagram, and FIG. 4 is a flow chart showing a communication path switching procedure. FIG. 5 is a conventional example. 1...Specific note, 2-5...Subordinate node, 10.
...Logical communication setting unit, 12-15...Physical backbone communication path, 20-21...Logical communication path, 23...Communication path between dependent nodes, 32-35...Communication path setting for failure avoidance Department,
45... Communication path between dependent nodes, 202-203...
Communication path, 220... Exchange switch, 221... Exchange switch control unit, 230... Traffic counting unit, 23
1... Transmission/reception error counting section, 233... First regulation setting section, 234... Second regulation setting section, 235... First regulation comparison section, 236... Second regulation comparison section, 237. ...Detour communication path selection section, 238...Detour communication setting section. Agent Patent Attorney Tsukasa Nakajima 3rd Seki A (2,3 Figure 4 Figure 5 EOEOEOEOEO

Claims (3)

[Claims] (1) In a data exchange system in which multiple dependent nodes are connected to a specific node via physical backbone communication channels, a failure avoidance communication path is laid between the dependent nodes, and a failure avoidance communication path is connected to the specific node. A plurality of connected subordinate nodes are regarded as one logical node, and each physical backbone communication channel connecting a specific node and each subordinate node constituting the logical node is used as a communication path for avoiding failures of other physical backbone communication channels. A logical communication path setting unit that forms a logical communication path that is considered as If no problem has occurred, the dependent node and the specific node are connected only through the physical backbone communication path, and when a failure occurs in the physical backbone communication path, the connection is switched to the failure avoidance communication path, A data exchange device is provided that connects the dependent node to the specific node via a failure avoidance communication path and a physical backbone communication path that is regarded as a failure avoidance communication path with other dependent nodes belonging to the same logical node. A data exchange system characterized by: (2) The data exchange system according to claim 1, wherein the subordinate nodes constituting the logical node are geographically adjacent to each other, or the transmission capacity of the communication path between them is low. (3) In a data exchange device that includes a plurality of communication paths used for communication with a plurality of other nodes and an exchange unit that selects a communication path to be activated from among the plurality of communication paths, the communication status of each communication path a transmission state monitoring unit that monitors the communication path; and a transmission state monitoring unit that selects another communication path as a detour circuit when a transmission failure occurrence state of any communication path among the communication paths is larger than a first predetermined value. a detour communication path selection unit that prepares the detour communication path for operation, and a detour communication path selection unit that prepares the detour communication path for operation when the transmission error occurrence state exceeds a first predetermined value and then becomes larger than a second predetermined value; What is claimed is: 1. A data exchange device comprising: a detour communication path setting section that controls the exchange section so as to instead operate the detour communication path selected by the detour communication path selection section.