JP2003124964A - Circuit redundant apparatus, and communication controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the increase of the load of a network and the generation of its invalied data, in the network system, made redundant, with switching devices. SOLUTION: In a circuit redundant apparatus 10, a fault-information managing portion 11 so checks the respective receiving states of line-A and line-B systems as to update at need a circuit-fault information 11a. The circuit-fault information 11a indicates the receiving states of respective nodes with respect to the respective line-A and line-B systems. When each node transmits a data, a data-transmission managing portion 12 so refers to the circuit-fault information 11a and so recognizes the respective receiving states of the line-A and line-B systems with respect to the node of the transmitting destination of each node as to transmit the data only to the normal line of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a redundancy device and a communication control method in a system in which a switch device exists on a plurality of network lines.

[0002]

2. Description of the Related Art Conventionally, a control device (for example, 10/100 Mbps) that provides a plurality of physical network lines logically as one line to an upper layer (application etc.)
In a device that realizes redundancy using multiple Ethernet lines (hereinafter referred to as a line redundancy device)), as a method for realizing network line redundancy, the same data is sent to all managed network lines during transmission. Is sent, and the receiving side notifies the upper layer (application) of one of multiple identical data received from multiple network lines (usually the first normal data received) and discards other data. There are methods.

[0003]

According to the above-mentioned conventional method, the line redundancy apparatus does not care about each network state under management or the network state up to the partner node in the processing at the time of transmission, and it does not affect all the lines. The same data will be transmitted.

However, in the case where the network has a switch device which will be described later in detail, the following problems occur. That is, if the redundant network uses a switch device and any of the components (switch device, cable, etc.) fails, the general characteristics of the switch device make There is a problem that data that does not flow (substantially invalid data) is generated, meaninglessly increases the network load, or invalid data flows into the connected device and wastefully increases the load on the connected device by the process of discarding it. It was

The switch device mentioned here is, for example, a "bridge", a "switching hub" or the like, and its basic general characteristics (functions) are roughly as follows. (1) The MAC (Media Access Control) addresses of all devices connected to the port are registered in each port (MAC layer; lower sublayer in the data link layer in the OSI model. MAC address; Ethernet ( (Registered trademark) Destination address added to packet header in communication). (2) This registration is performed when the data from the device is received. (3) The MAC address once registered is deleted when no data is received from the corresponding port within a certain period of time (aging time: customizable). (4) The data received from a certain port is the destination MA
Forward to the port where the C address is registered. If there is no corresponding port, forwarding is done to all ports.

Among the above-mentioned general characteristics, there is a characteristic that "when there is no corresponding port, forwarding is performed to all ports", so that the above-mentioned problems occur. The above problem will be described below with reference to FIG. 5 while showing a specific example.

In the network shown in FIG. 5, the node 1, the node 2 and the node 3 respectively have line redundancy devices 4, 5, 6 respectively.
Is connected to a network (line A system, line B system) via. In addition, the switch device A is installed in the line A system.
1, the switch device A2 is provided, and the line B system is provided with the switch device B1 and the switch device B2.

In FIG. 5, assuming that communication is being performed from both sides between node 1 and node 2, node 2
Assuming that the cable to the line B system (the cable that connects the line redundancy device 5 and the switch device B2) has a disconnection failure, 1) When the data is transmitted from the node 2 to the node 1, the line redundancy is performed. The device 5 transmits data to both the line A and B systems regardless of the network state as described above, but is transmitted to the line A system (indicated by an alternate long and short dash line arrow in the figure) but not to the line B system. (It does not reach the switch device B2). 2) However, the transmission data from the node 1 is the lines A and B.
It is transmitted to both systems. In the switch A2 of the line A system, the transmission destination MA of the transmission data from the node 1 to the node 2
Forward only to the port where the C address is registered (the port to which the node 2 is connected). On the other hand, in the B system switch B2, after the aging time, the MAC address of the node 2 registered in the port to which the node 2 is connected is deleted, and the port of the node 2 with the MAC address registered disappears. ,
After that point, the transmission data from the node 1 to the node 2 is forwarded to all ports of the own device. 3) As a result, part of the data that was originally transmitted and received only between node 1 and node 2 (only the data from node 1 to node 2) is also transmitted to the node 3 side that is not originally related (Fig. (Indicated by a dotted arrow in the middle), a process of receiving and discarding data that has no meaning on the node 3 side is performed.

In the illustrated example, the node and the line redundancy device are shown separately, but the line redundancy device may be considered as a part of the configuration within the node (for example, the communication control unit).
An object of the present invention is to increase or invalidate a network load due to general characteristics of a switch device in a redundant network system, particularly when a switch device is provided on the network, when a partial failure of the network occurs. An object of the present invention is to provide a redundancy device and a communication control method capable of suppressing the generation of data.

[0010]

A redundancy device according to the present invention is provided in each node connected to a plurality of lines provided with a switch device, and transmits the same data to all lines at the time of transmission, Each time data is received, it is determined whether or not a failure has occurred in the part related to the source node for each of the plurality of lines, and if it is determined that a failure has occurred, the failure occurrence information is recorded. And a data transmitting unit that does not transmit data to a line in which a failure occurs by referring to the failure occurrence information when transmitting data to an arbitrary node.

According to the redundant device having the above configuration, even when the switch device is provided on the redundant network, there is a failure somewhere in each component (switch device, line, etc.). In this case, it is possible to prevent a situation in which data that should not originally flow (substantially invalid data) occurs on the network due to the general characteristics of the switch device.

The switch device is, for example, a bridge, a switching hub or the like. Further, the communication control method according to the present invention is a communication control method in a redundancy device which is provided for each node connected to a plurality of lines provided with a switch device and which transmits the same data to all the lines at the time of transmission. When data is received from an arbitrary node from the system, it is monitored whether data is received from the same node from another system within a predetermined time, and if no data is received,
At least on the assumption that a failure has occurred in the part related to the node in the other system, the failure information is registered, and at the time of data transmission, the registered failure information is referred to,
If there is a system having a failure with respect to the destination node, no data is transmitted to the system having the failure.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram of a line redundancy device according to this example.

The line redundancy device 10 shown in the figure is provided with a line A side driver 13 and a line B side driver 14 which have existed in the past, and in this example, a fault information management section 11 (line fault information 11a) and data transmission. It has a management unit 12 and the like (note that portions not directly related to this description are omitted).

Although FIG. 1 shows an example in which the plurality of network lines are two lines, the present invention is not limited to this. The failure information management unit 11 manages the failure status of each line. That is, the failure information management unit 11 determines from which line (line) data is received from which node, that is, whether data from a certain node is received from both the lines A and B, or from only one side. Always check if it is not received, and if necessary, line failure information 11
Update / manage a.

A processing example of the failure information management unit 11 will be described with reference to FIG. In FIG. 2, first, when arbitrary data transmitted from an arbitrary node is received from one of the A system / B system lines (step S1,
YES), it is checked whether data from the same node is received from the other system within a predetermined time (step S).
2, S3).

When data from the same node is received from the other system within a predetermined time (step S2, YE
S), it is determined that both systems are normal (step S6),
The process ends.

On the other hand, if data is not received from the same node from the other system within the predetermined time (step S
(3, YES), it is determined that some abnormality has occurred in at least the part related to the "same node" in the other system (step S4). Then, the line failure information 11a is updated based on this determination (step S
5). In the example of the line failure information 11a shown in FIG. 1, some abnormality occurs in the portion related to the node 3 for the line A system, and some abnormality occurs in the portion related to the node 4 for the line B system. Each shows the line failure information when the above update is performed.

The step S2 means that it is only necessary to check whether or not the data from the same node is received, and it is not necessary to check whether or not the same data is received. (That is, different data may be used as long as the data is from the same node) because the failure information management unit 11 is a functional unit whose purpose is to detect a failure on the line. is there. That is, for example, if the data from a certain node is received from the A system and then the data from the B system is not received within a predetermined time,
It can be judged that there is something wrong with the system, and even if the received data from the B system is "different data", if it is sent from the same node, there is a problem on the B system line. There will be no.

Although not particularly mentioned in the above description,
Naturally, a normal reception process is also performed by a reception processing unit (not shown) or the like. Whether or not the same data has been received may be checked by, for example, the reception processing unit when relaying the received data to an upper layer (application layer or the like). Alternatively, the failure information management unit 11 may be considered to be a part of the function of the reception processing unit.

The method of detecting a failure on the line is not limited to the above method. For example, “whether there is any received data within an arbitrary monitoring cycle time” is independently checked for each of the A system and the B system (regardless of whether the other system has received data). You may do it.

When performing the data transmission processing requested by the host (node 1) of the line redundancy device 10, the data transmission management unit 12 refers to the line failure information 11a and sets the target data to the lines A and B. The transmission processing is performed after determining / determining whether the data is transmitted to either one or both.

An example of this transmission process will be described with reference to FIG. In the transmission process of transmitting arbitrary data to an arbitrary destination node, the data transmission management unit 12 does not always transmit the data to all systems as in the conventional case, but determines a line to be transmitted and then transmits the line.

In FIG. 3, the data transmission management unit 12 is
When there is a transmission request from the upper layer, first, in order to determine the destination line, the line failure information 11a managed by the failure information management unit 11 is referred to (step S11),
The reception status data (failure information) of each system for the destination node is obtained, and the normality / abnormality of each system for the destination node is determined based on this (step S12).

If only one of the A system and the B system is abnormal (step S12, YES), that is, A
If the system is normal and the system B is abnormal, or if the system A is abnormal and the system B is normal, transmission is performed only to the line that is normal, and transmission to the line that is defective is not performed (step S14). For example, in the example shown in FIG. 1, when the destination node is the node 3, data is transmitted only to the line B system, and when the destination node is the node 4, data is transmitted only to the line A system. .

On the other hand, when both systems are judged to be normal or both systems are abnormal (step S12, NO),
Data transmission to both A and B systems is executed (step S1).
3). For example, in the example shown in FIG. 1, when the destination node is the node 2, both systems are normal.
Executes data transmission to both A and B systems.

Here, as described above, not only when both systems are normal, but when it is determined that both systems are abnormal, it is decided to execute data transmission to both A and B systems.
This is because the situation described below has been taken into consideration.

That is, for example, when a failure such as a power failure occurs in a certain node (referred to as a corresponding node), in the other nodes, the data received from this node is lost in both the A and B systems, so both systems are It is determined to be abnormal, and the corresponding node is managed as "abnormal" in both the A and B systems in the line failure information 11a. After that, when the relevant node recovers from the power failure, both A and B systems will be normal, but other nodes will manage both A and B systems as "abnormal" until data is received from the relevant node. Therefore, if both A and B systems are "abnormal", if data transmission is not performed, data transmission to the corresponding node cannot be performed during that time.

FIG. 4 is a diagram schematically showing an example of the hardware configuration of the line redundancy device. In the example shown,
Although it is configured to include the CPU 21, the storage unit 22, the communication control unit 23, and the like, other configurations may be provided.

The storage unit 22 stores the line failure information 11a. In addition, the processing shown in FIG. 2 and FIG.
A program to be executed by 21 is stored. The communication control unit 23 connects to a network and controls data transmission / reception.

As described above, according to the line redundancy device of this example, (1) cable failure from the line redundancy device to the duplex line on the Ethernet duplex line (2) any line on the duplex line In the event of a failure such as a switch device or cable failure, or due to an artificial connection error, the line redundancy device will operate on each destination node even after the aging time of each switch device has elapsed. Since data is sent only to the appropriate (normal) line, nodes other than the concerned node do not receive invalid data, the load on the network itself increases and CPU load due to invalid data reception and discarding on other nodes. It is possible to suppress the rise.

[0032]

As described above in detail, according to the redundancy device and the communication control method of the present invention, in the system in which the switch device exists on a plurality of network lines,
It is possible to suppress an increase in network load and generation of invalid data due to general characteristics of the switch device when a partial failure of the network occurs.

[Brief description of drawings]

FIG. 1 is a functional block diagram of a line redundancy device according to this example.

FIG. 2 is a flow chart diagram for explaining a processing example by a failure information management unit.

FIG. 3 is a flow chart diagram for explaining an example of a transmission process by a data transmission management unit.

FIG. 4 is a diagram schematically showing an example of a hardware configuration of a line redundancy device.

FIG. 5 is a diagram for explaining a conventional problem.

[Explanation of symbols]

10 Line redundancy device 11 Failure Information Management Department 11a Line failure information 12 Data transmission management section 13 Line A side driver 14 Line B side driver 21 CPU 22 Memory 23 Communication control unit

Claims (4)

[Claims] 1. A redundancy device, which is provided for each node connected to a plurality of lines provided with a switch device and transmits the same data to all lines at the time of transmission, for each data reception, for each of the plurality of lines, It is determined whether or not a failure has occurred in the part related to the node of the transmission source, and when it is determined that a failure has occurred, failure information management means for recording the failure occurrence information, and A redundant device comprising: a data transmitting unit that does not transmit data to a line in which a failure has occurred by referring to the failure occurrence information at the time of data transmission. 2. The fault information management means may include another line that does not receive data from the same node within a predetermined time from the time when data is received from an arbitrary node from one of the plurality of lines. 2. The redundancy device according to claim 1, wherein in the case of a failure, it is determined that a failure has occurred in a portion related to the same node in the other line. 3. The redundancy device according to claim 1, wherein the switch device is a bridge or a switching hub. 4. A communication control method in a redundancy device, wherein a switching device is provided for each node connected to a plurality of lines, and the same data is transmitted to all the lines at the time of transmission, which is arbitrary from any system. When receiving the data from the node,
It monitors whether or not data is received from the same node from other systems within a predetermined time. If no data is received, it is considered that at least a part related to the node in the other system has failed. Then
When the failure information is registered and the data is transmitted, the registered failure information is referred to, and if there is a system having a failure with respect to the destination node, data transmission to the system having the failure is not performed. A characteristic communication control method.