JPH07177171A - Network connection controller - Google Patents

Abstract

PURPOSE:To provide a network connection controller detecting a terminal equipment having a fault early and confirming restoration of the faulty terminal equipment early. CONSTITUTION:The controller is provided with a network A17a to which plural terminal equipments are connected, a network B17b to which other plural terminal equipments are connected, a network A transmission reception processing section 14a and a network B transmission reception processing section 14b implementing communication processing among the terminal equipments, a network A faulty terminal equipment address storage section 10a and a network B faulty terminal equipment address storage section 10b storing an address of a terminal equipment having a communication fault, and returns a signal indicating a terminal equipment fault to a terminal equipment sending a text when a destination address in the text received from an optional terminal equipment is coincident with an address of a terminal equipment stored in the faulty terminal equipment address storage means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication between terminals on different networks, and communication between terminals on different networks when physically connected to different networks, which enables confirmation of the presence or absence of a connected terminal at the OSI layer 2 level. The present invention relates to a network connection control device for controlling communication of a terminal.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to FIGS. FIG. 5 is a diagram showing an example of a network configuration in which two different networks are connected, and FIG.
FIG. 7 is a diagram showing a virtual network configuration when viewed from a terminal on the network shown in FIG. 5, FIG. 7 is a diagram showing an example of a message format when the network shown in FIG. 6 is HBS, and FIG. FIG. 9 is a diagram showing a configuration example of a network connection control device according to a conventional technique, FIG. 9 is a diagram showing an example of normal exchange of electronic messages when the conventional network connection control device is used, and FIG. 10 is a conventional network connection control FIG. 11 is a diagram showing an example of exchange of electronic messages required for a terminal on one network to detect an abnormality of a terminal on the other network when using a device. FIG. 11 shows a case where a conventional connection control device is used. It is a figure which shows an example of the exchange of the electronic message required until the terminal on one network detects abnormality of the terminal on the other network, and confirms restoration.

A conventional example will be described below by taking the case where the network shown in FIG. 5 is an HBS as an example. According to the standard, HBS has a message format (priority code 7
1 to the frame check code 77) and its reception response 79 at the layer 2 level are transmitted and received on the control channel (details of the meaning of each code are EIAJ standard ET.
-2101). The network A 17a and the network B 17b shown in FIG.
In the system connected by, the two networks are both HBS.

Now, the terminal A1 on the network A17a
(51) is the terminal B1 (53) on the network B17b
A transmission / reception process between terminals according to the conventional example will be described by taking as an example a case where a telegram requesting a response at the layer 7 level is sent to.

The terminal A1 (51) is controlled by the network connection control device 16 as shown in FIG.
Will physically perform the same communication control as if they are on the same network A60.

The operation of the conventional network connection control device 16 that enables this will be described with reference to FIG. In the network A transmission / reception processing unit 81a, the network A 17a
When receiving a telegram (see FIG. 7, PR71 to FCC77) flowing above, whether or not the telegram is a broadcast telegram is determined by the instruction of the PR71 part. If the telegram is a 1-byte response ACK / NAK7
Although no response is given in No. 9, if it is a non-broadcast message, it is determined whether it is a self-addressed message. In this determination processing, if the value stored in the self-address storage unit 15 and the value of the destination address DA73 in the message match, an ACK response is returned and the message is passed to the self-addressed message control processing unit A13a. If it is a self-addressed message, first, the destination address DA7 in the message is stored in the network B connection terminal address storage unit 11b.
Check whether the address of the terminal specified in 3 exists. If the address exists, some response is returned, but if the address does not exist, no response process is performed. By this processing, as shown in FIG. 6, it is possible to control each terminal so that the terminal A1 (51) and the terminal B1 (53) are on the same network A60 at the OSI layer 2 level.

Next, the network connection control device 80
After such a series of processing is completed, the received message is passed to the non-self addressed message control processing unit A12a.

The non-self-addressed message control processing unit A12a confirms the value of the 1-byte response ACK / NAK79 of the received message, and when there is an ACK response, the destination address DA73 is further set to the network A connection terminal address storage unit 11.
It is confirmed whether it exists in a, and when it exists, the received message is discarded because it is a message that does not need to be transmitted to the network B17b. Even if there is an ACK response, if the destination address DA73 does not exist in the network A connection terminal address storage unit 11a, the received message is sent to the network B.
It is passed to the transmission / reception control processing unit 81b. When there is no ACK response, it is determined whether it is a broadcast message, and when it is not a broadcast message, the message is discarded. Further, when there is no ACK response and when it is a broadcast telegram, the telegram is passed to the network B transmission / reception control processing unit 81b. By this process,
Only the required telegrams will be sent on the other network.

In the network B transmission / reception control processing unit 81b to which the received message from the network A 17a is transferred, P
Send the message from R71 to FCC77 and execute AC
Wait for K / NAK79 response. It is confirmed whether or not there is a response other than no response as the ACK / NAK79 response, and if there is a response, the destination address DA73 in the transmission message is sent.
Address of network B connection terminal address storage unit 1
1b, and the process ends. If there is no response,
If it is a broadcast message, the processing is terminated. If it is a non-broadcast message, the address of the destination address DA73 is deleted from the network B connection terminal address storage unit 11b. .

An example of a network connection control device to which the present invention is applied is described in Japanese Patent Application No. 3-216920 (Japanese Patent Application Laid-Open No. 5-5).
3953) for details.

By using such a conventional network connection control device 80, the construction of a system in which the terminal is not aware of physical expansion has been realized.

Now, the terminal A1 on the network A17a
(51) is the terminal B1 (53) on the network B17b
When sending a message holding a command requesting a response to the DATA76 area to the terminal A1 (51), the terminal B
A case where both 1 (53) are normal will be described as an example with reference to FIG. 9 by referring to FIG. 9.

First, the terminal A1 (51) transmits 90a a message in which the address of the terminal B1 (53) is designated as the partner address DA73 to the network A17a 90a, and the network connection control device 80 receives this message. At this time, since the terminal B1 (53) exists on the network B17b connected by the network connection control device 80, the network connection control device 80 ACKs the terminal A1 (51) as a 1-byte response 79 by the above-mentioned function. The response is returned 90b. Also, the received telegram is transmitted 91a to the network B17b, and the terminal B1 (53) sends the AC
The K response is returned 91b.

Next, the terminal B1 (53), which has received the message from the terminal A1 (51), executes the command process 92 and sends a response message in which the address of the terminal A1 (51) is designated as the partner address DA73 on the network B17b. Send to 93a
Then, the ACK response from the network connection control device 80 is received 93b. The network connection control device 80, which has received the response message 93a, connects the terminal A to the network A17a.
1 (51) exists, terminal A
1 (51) sends a response message 94a, and the terminal A1 (5
94b is received from the ACK response from 1).

Further, when the terminal A1 (51) transmits 95a a message with the network connection control device 80 as the partner address DA73, the network connection control device 80 transmits an ACK response 95b. Do not pour onto B17b. Similarly, the terminal Bn54
However, when the terminal B1 (53) sends a message 96a with the partner address DA73 and the terminal B1 (53) sends back a response 96b, the network connection control device 80 causes the network connection control device 80 to send a message to the terminal B1 (53) and the terminal Bn54. Although it is monitoring the sending and receiving of, the data is not sent to the network A17a.

[0016]

Next, in the exchange of a message between terminals on different networks, the terminal A1 when a failure occurs in the terminal B1 (53) and an abnormality occurs in the receiving function. A conventional example of the abnormality detection in (51) is shown.

In FIG. 10, it is assumed that the terminal A1 (51) transmits 100a to the terminal B1 (53) a message requesting a response similar to that shown in FIG. At this time, in the conventional network connection control device 80, the terminal B1 (53)
B1 (5
It recognizes only the existence of 3) and sends A to terminal A1 (51).
After transmitting the CK response 100b, the electronic message is transmitted 101aa to the terminal B1 (53). However, terminal B1 (53)
Terminal B1 (53) because there is an abnormality in the 1-byte response function of
However, in the HBS standard in this example, if there is an abnormality at the layer 2 level, the retransmission is repeated 3 times, and the network connection control device 80 and the terminal B1 are transmitted. Similar exchanges are repeated between (53) (101bb-101d)
b). At this time, as shown in FIG. 9, the terminal A1 (5
1) is designed to wait for a response at the application level from the terminal B1 (53) for a fixed time (hereinafter referred to as Tout time), but if there is no response after the Tout time elapses, at the application level. Retransmission of 102a
I do. In response to this retransmission, the network connection control device 80 returns a layer 2 level ACK response 102b.
Then, the same transmission / reception processing as described above is performed with the terminal B1 (53) (103aa to 103db). Normally, retransmission processing at the application level is also performed three times (102a
~ 106b), the terminal A1 (51) will detect 108 an abnormality of the terminal B1 (53) when the time of [4 x Tout time] finally elapses, and the Tout time must be increased. In the application, there is a problem that it takes too long to detect an abnormality.

Further, as shown in FIG. 11, once the terminal B1
The terminal A1 (51) which has recognized the abnormality (53) 110,
Next, as a method for confirming the recovery of the terminal B1 (53), if the terminal B1 (53) is not designed to send a message to itself to the terminal A1 (51),
The terminal A1 (51) must periodically send 111a a telegram for confirmation to the terminal B1 (53). Also at this time, the network connection control device 80 sends an ACK
The response is returned 111b, and the above-mentioned [4 × Tou
t hours] will be taken for confirmation. Finally, after transmitting the electronic message 113a several times, T
When the response message 117a is received within the Tin time shorter than the out time, the terminal A1 (51) recognizes 118 that the terminal B1 (53) has recovered. At this time, the terminal A1 (51) cannot recognize how much time has elapsed since the terminal B1 (53) was actually restored, and the terminal B1 ( 5
There is a problem at the application level such that the function 3) cannot be used in the terminal A1 (51) for a long time.

In consideration of such problems of the conventional network connection control device, the present invention provides a network connection control device capable of early detection of an abnormal terminal and early confirmation of recovery of the abnormal terminal. It is intended.

[0020]

According to the present invention of claim 1, a first network to which a plurality of terminals are connected, a second network to which another plurality of terminals are connected, and the first network
And communication between the terminals on the first network, between the terminals on the second network, or between the terminals on the first network and the terminals on the second network. In the network connection control device including the transmission / reception control processing means for performing, the transmission / reception control processing means has abnormal terminal address storage means for storing the address of the terminal in which the communication abnormality occurs, and Is a network connection control device that returns a signal indicating a terminal abnormality to the terminal that has transmitted the message when the destination address of the terminal matches the address of the terminal stored in the abnormal terminal address storage means.

According to the present invention of claim 2, a first network to which a plurality of terminals are connected, a second network to which another plurality of terminals are connected, and a connection between the first and second networks are provided. Transmission / reception control processing means for performing communication processing between terminals on the first network, terminals on the second network, or terminals on the first network and terminals on the second network. In the network connection control device, the transmission / reception control processing means includes an abnormal terminal address storage means for storing an address of a terminal in which an abnormality has occurred in communication, and a terminal failure occurrence instruction means for notifying the terminal abnormality to all or part of the terminal. And a network connection control device including.

[0022]

According to the present invention of claim 1, the transmission / reception control processing means comprises:
When the destination address in the message received from any terminal matches the address of the terminal stored in the abnormal terminal address storage means, a signal indicating a terminal error is returned to the terminal that sent the message.

According to the second aspect of the present invention, the abnormal terminal address storage means stores the address of the terminal in which the communication abnormality has occurred, and the terminal failure occurrence instruction means notifies the terminal abnormality to all or part of the terminal. To do.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing its embodiments.

FIG. 1 is a diagram showing the configuration of a network connection control apparatus according to the first embodiment of the present invention.
FIG. 6 is a diagram showing exchange of electronic messages required for a terminal on one network to detect an abnormality of a terminal on the other network when using the network connection control device.

This embodiment will be described by taking as an example the case where both the network A17a and the network B17b shown in FIG. 5 are HBSs. The network connection control device 16 according to the present invention is a conventional network connection control device 80.
The difference is that a network A abnormal terminal address storage unit 10a and a network B abnormal terminal address storage unit 10b are newly provided, and the network A transmission / reception processing unit 14a is provided.
The network B transmission / reception processing unit 15b performs the following processing.

The network A transmission / reception processing unit 14a uses ACK / N when transmitting an individual message to the network A 17a.
When a NAK response that is not a response is received even after the retransmission process is completed at the time of confirming the AK response 79, the address of the terminal indicated by DA 72 in the electronic message is stored in the network A connection terminal address storage unit 11a, and at the same time, the network A abnormal terminal is stored. It is also stored in the address storage unit 10a. The network B transmission / reception processing unit 14b also performs the same processing, and the network B17
The abnormality of the terminal on the terminal b is stored in the network B abnormal terminal address storage unit 10b. When a message is received from a terminal on the network A 17a, the network A transmission / reception processing unit 14a
Then, in addition to the conventional processing when receiving a message, the network B1
At the time of receiving an individual message to the terminal on 7b, the value of the destination address DA73 in the received message is further compared with the value in the network B abnormal terminal address storage unit 10b, and if a matching address exists, , NA indicating a terminal failure when sending ACK / NAK 79 response of received message
After sending the K response, the received message is discarded. Network B
The same processing is performed by the network B transmission / reception processing unit 14b for the electronic message on 17b.

Here, in FIG. 1, the network A transmission / reception processing unit 14a and the network B transmission / reception processing unit 14 are shown.
b, non-self-addressed message control processing unit A12a, non-self-addressed message control processing unit B12b, network A abnormal terminal address storage unit 10a, network B abnormal terminal address storage unit 1
0b and the like constitute transmission / reception control processing means.

Next, the operation of the network connection control device of the above embodiment will be described with reference to the drawings.

First, the terminal A1 on the network A17a
(51) is the terminal B1 (53) on the network B17b
When sending a message holding a command requesting a response to the DATA76 area to the terminal A1 (51) and the terminal B1 (5
3) When both are normal, the conventional processing shown in FIG. 9 is realized.

On the other hand, when some trouble occurs in the terminal B1 (53) and an abnormality occurs in the receiving function, the terminal A1 (5)
The operation at the time of abnormality detection in 1) will be described.

As shown in FIG. 2, the terminal A1 (51) transmits 20a a telegram requesting a response similar to that shown in FIG. 9 as an example in the case where the terminal B1 (53) is normal. At this time, the network connection control device 16 is still in the terminal B1.
Since the abnormality in (53) has not been detected, an ACK response is returned 20b to the terminal A1 (51). After that, terminal B1 (53)
The received message is transmitted to the terminal 21a, but the terminal B where the abnormality has occurred
From 1 (53), a NAK response is returned 21b, and subsequently, as a process at the time of receiving the NAK response, three retransmissions (22a to 22a) are performed.
4a) is performed, and NAK responses are returned (22b to 24b) as respective responses. Then, the network connection control device 16 detects 251 that the terminal B1 (53) is abnormal. At this point, the network connection control device 1
6 stores the address of the terminal B1 (53) in the network B abnormal terminal address storage unit 10b.

At this time, the terminal A1 (51) is an application as it is in the past and cannot wait for the response message from the terminal B1 (53), and the timeout Tout time for the retransmission processing at the application level elapses. Later, the electronic message to the terminal B1 (53) is transmitted 26a again. Then, the network connection control device 16 determines that the terminal B1
Since the abnormality of (53) has already been recognized, the NAK response at the layer 2 level is returned 26b, and then the terminal A1
Retransmission processing is performed at the layer 2 level between (51) and the network connection control device 16 (27a to 29).
b). As a result, the terminal A1 (51) detects 252 that the terminal B1 (53) is abnormal at this point. Here, the retransmission interval at the layer 2 level is much smaller than the retransmission interval at the application level (for example, in HBS, the retransmission interval at the layer 2 level is on the order of 10 msec, whereas the retransmission interval at the application level is on the order of several seconds. Therefore, the abnormality of the terminal B1 (53) can be recognized in a time shorter than [2 × Tout time], that is, approximately Tout time.

According to the above-described embodiment, it is possible to shorten the time required for confirming the failure of the partner terminal at the message transmitting terminal, which is one of the problems in the conventional example. Next, in the above-described embodiment, it is not possible to reduce the processing on the side of the message transmitting terminal for confirming the recovery of the terminal in which the failure has been confirmed, as shown in FIG.
Another issue, the reduction of failure / restoration recognition processing on the terminal side, cannot be fulfilled. Therefore, as a second embodiment of the present invention, the commands shown in FIG. 4 are provided, and in the network connection control device 16 (the basic configuration is the same as that of FIG. 1, description will be made with reference to FIG. 1). When a 1-byte response error is detected and an error is detected, the command is broadcast to both networks. In this embodiment, a part of the network A transmission / reception processing unit 14a, the network B transmission / reception processing unit 14b, and the like constitutes a terminal failure occurrence instruction unit. Terminal A1 (51) becomes terminal B1 (5
3 and 4 in the case of transmitting a message to 3)
Also, description will be made with reference to FIG.

FIG. 3 is a diagram for explaining the operation of detecting an abnormality in the terminal and confirming the recovery when the network connection control apparatus of the second embodiment according to the present invention is used.

First, the terminal A1 (51) is connected to the terminal B1 (5
3), the destination address DA73 transmits 30a a message indicating the terminal B1 (53) to the network A17a. The network A transmission / reception processing unit 14a of the network connection control device 16 receives this message, and the network B
Since the address of the terminal B1 (53) exists in the connected terminal address storage unit 11b and the address of the terminal B1 (53) does not exist in the network B abnormal terminal address storage unit 10b, the terminal A1 (51) is The ACK response is transmitted 30b. The received message is also passed to the network B transmission / reception processing unit 14b via the non-self addressed message control processing unit A12a.

Next, the network B transmission / reception processing unit 14b
Sends the passed message to the terminal B1 on the network B17b.
Although it is sent 31a to (53), a NAK response 31b is returned when the terminal B1 (53) fails. If the ACK response is not obtained even after repeating the retransmission four times (32a to 34b), the network B transmission / reception processing unit 14b determines the terminal B
No. 1 abnormality 351 is detected, the address of the terminal B1 (53) is stored in the network B abnormal terminal address storage unit 10b, the transmission message is discarded, and then the network A transmission / reception processing unit 1
4a and the network B transmission / reception processing unit 14b broadcast the commands (41a, 41b) shown in FIG.
The electronic message which is included as the OPR763 and whose transmission source address SA72 is the address of the terminal B1 (53) is transmitted 36.
The terminal A1 (51), which has received the electronic message including this command with terminal failure (41a, 41b), detects the abnormality of the terminal B1 (53) by checking the layer 2 level source address SA72 in the received electronic message 352a. Yes, terminal A
All terminals other than 1 (51) also receive terminal B1 when receiving a message.
The abnormality (53) can be detected 352b, 352c, 352d. As a result, even if there is a terminal other than the terminal A1 (51) that attempts to send a message to the terminal B1 (53), the abnormality of the terminal B1 (53) has already been detected, and thus it is useless. There is no need to send a message.

Further, the network connection control device 16 is
After the abnormality is detected, a telegram that does not require application processing is periodically transmitted to the terminal B1 (53), and the ACK / NAK response is confirmed. Then, when the terminal B1 (53) returns 37b an ACK response to the message 37a transmitted by the network connection control device 16,
The network connection control device 16 confirms 381 that the terminal B1 (53) is restored, and broadcasts to both networks simultaneously the command (42a, 42a) without the terminal failure shown in FIG.
b) is included as the OPC 762 and OPR 763, and the transmission source address SA 72 transmits a message which is the address of the terminal B 1 (53) 39. This terminal failure-free command (42
terminal A1 (51) that has received a telegram containing a, 42b)
Is the source address SA at the layer 2 level in the received message
By confirming 72, the abnormal recovery of the terminal B1 (53) can be detected 358a, and all terminals other than the terminal A1 (51) can also detect the abnormal recovery of the terminal B1 (53) at the time of receiving the electronic message 358b, 358c, 358d. . This eliminates the need for any terminal to periodically send a message to confirm the recovery of the terminal in which the abnormality has occurred.

When the command structure for this notification has the one-byte structure of each of the OPC 762 and OPR763 shown in (1) and (2) of FIG. 4, there is an advantage that the message length can be kept short. However, on the other hand, at each terminal that has received a message containing them in the message, the layer 2 is generated even though it is at the application level (layer 7 level).
The problem remains that you have to check the address of the level. Therefore, a command ((3) that fetches the terminal address of failure occurrence and failure recovery into the OPR763 as well.
43c and 44c of (4)), the processing load at the application level can be further reduced.

As described above, when a NAK response other than no response is detected as a response at the OSI layer 2 level a plurality of times in succession when a message is transmitted to the terminal connected to the network, it is regarded as a terminal abnormality and an abnormality is detected. The address information of the detected terminal is held, and when the proxy response at the layer 2 level of the terminal on another network is received when the message is received, the destination address in the received message is the address of the terminal where the abnormality is detected. Judge whether they match, and if they match,
It is configured to send back a NAK response indicating a terminal failure, discard the received message, and periodically perform processing by an application for a terminal that holds address information as a terminal in which an abnormality is detected. Send individual non-telegrams individually OSI
On the other side of the network by confirming the layer 2 level response and deleting the information of the terminal that returned the ACK response from the address information of the terminal that detected the abnormality when the ACK response was detected. The occurrence / cancellation of an abnormal situation in which a NAK response is returned at the layer 2 level of the communication partner terminal can be detected as quickly as possible by the message sending side terminal without changing the application of the sending / receiving terminal.

Further, as a command capable of notifying the information of the terminal in which the abnormality of the OSI layer 2 level response is detected, a command composed of an operation code portion indicating the abnormality notification and an operand code portion indicating the address of the abnormal terminal. When a message is transmitted to a terminal and an abnormal response at the layer 2 level of OSI is detected, the command is broadcast to each network in a broadcast manner. As a command that can notify the information of the terminal where the abnormality of the response has been released, a command composed of an operation code part indicating the error release and an operand code part indicating the address of the error release terminal is provided, and when sending a message to the terminal, When the cancellation of the abnormality is detected, the command is sent to each network when the OSI layer 2 level response is detected. By configured to transmit at broadcast above, when the generation / release of the abnormal situation has occurred, even if there is no access from the application can allow recognize the situation.

Therefore, the occurrence / cancellation of an abnormal situation in which a NAK response is returned at the layer 2 level of the terminal of the communication partner on one network does not occur at the terminal on the same network without changing the application of the transmitting / receiving terminal. Can be recognized in almost the same time as the occurrence of (the layer 2 level abnormality of a terminal on a different network can be recognized in less than 1/3 of the conventional time), and the occurrence / cancellation of an abnormal situation At the time of occurrence, it will be possible to recognize the situation even if there is no access from the application, the need for confirmation work taken by the application will disappear when an abnormality occurs, the load on the application will be reduced, It is possible to reduce the traffic on each network due to the occurrence of an abnormality.

In the above embodiment, the terminal failure occurrence instructing means is configured to notify all terminals of the address of the terminal in which the abnormality has occurred, but instead of this, for example, only the terminal connected to one network is used. It may be configured to notify the.

Further, in the above-mentioned embodiment, each processing unit is constituted by dedicated hardware, but instead of this, the same function may be realized by software using a computer.

[0045]

As is apparent from the above description, the present invention has an advantage that it is possible to detect an abnormal terminal at an early stage and confirm the recovery of the abnormal terminal at an early stage.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a network connection processing device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an operation of detecting a terminal abnormality in the first embodiment.

FIG. 3 is a diagram illustrating an operation of detecting a terminal abnormality and confirming terminal recovery according to a second embodiment of the present invention.

FIG. 4 is a diagram showing an example of a command configuration according to the second embodiment.

FIG. 5 is a diagram showing an example of a network configuration.

6 is a diagram showing a virtual network configuration as viewed from a terminal on the network shown in FIG.

FIG. 7 is a diagram showing an example of a message format when the network shown in FIG. 6 is HBS.

FIG. 8 is a diagram showing a configuration of a conventional network connection control device.

FIG. 9 is a diagram showing an example of a normal operation when a conventional network connection control device is used.

FIG. 10 is a diagram showing an example of an operation for detecting a terminal abnormality when a conventional network connection control device is used.

FIG. 11 is a diagram showing an example of an operation of confirming the recovery after detecting a terminal abnormality when a conventional network connection control device is used.

[Explanation of symbols]

 10a Network A abnormal terminal address storage unit 10b Network B abnormal terminal address storage unit 14a Network A transmission / reception processing unit 14b Network B transmission / reception processing unit 17a Network A

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G06F 15/00 310 D 7459-5L 15/16 470 E H04L 12/66

Claims (6)

[Claims] 1. A first network to which a plurality of terminals are connected, a second network to which another plurality of terminals are connected, and a connection between the first and second networks, wherein A network including transmission / reception control processing means for performing communication processing between terminals on a network, terminals on the second network, or terminals on the first network and terminals on the second network In the connection control device, the transmission / reception control processing means has abnormal terminal address storage means for storing an address of a terminal in which an abnormality has occurred in communication, and a destination address in a message received from an arbitrary terminal is the abnormal terminal. When the address of the terminal stored in the address storage means matches, a signal indicating a terminal abnormality is returned to the terminal that transmitted the message. Network connection control device. 2. A first network to which a plurality of terminals are connected, a second network to which a plurality of other terminals are connected, and a connection between the first and second networks, the first network A network including transmission / reception control processing means for performing communication processing between terminals on a network, terminals on the second network, or terminals on the first network and terminals on the second network In the connection control device, the transmission / reception control processing means includes an abnormal terminal address storage means for storing the address of a terminal in which an abnormality has occurred in communication, and a terminal failure occurrence instruction means for notifying all or part of the terminal abnormality. And a network connection control device. 3. The transmission / reception control processing means, when a NAK response other than no response is detected a plurality of times as a response to the transmission of a message to the terminal in succession, the abnormal terminal address storage unit stores the other party The network connection control device according to claim 1, wherein the network connection control device stores an address. 4. The transmission / reception control processing means transmits a telegram that does not affect the application service to a terminal having an address stored in the abnormal terminal address storage unit at every predetermined time, and when an ACK response is returned, 4. The network connection control device according to claim 1, wherein the address of the abnormal terminal is deleted from the abnormal terminal address storage unit. 5. The terminal failure occurrence instruction means uses a terminal failure occurrence instruction command having an operation code section for notifying a terminal abnormality and an operand code section for indicating the address of the abnormal terminal to the terminal. When a NAK response other than the non-response is detected as a response to the message transmission, the simultaneous broadcast of the terminal failure instruction command to the first and / or the second network does not require a confirmation response. The network connection control device according to claim 2, wherein the network connection control device is transmitted. 6. The transmission / reception control processing means transmits a telegram that does not affect the application service to a terminal having an address stored in the abnormal terminal address storage unit at every predetermined time, and when an ACK response is returned, By using a terminal failure release instruction command including an operation code section for notifying that the terminal failure has been released and an operand code section for showing the terminal address for releasing the failure, the first and / or the first 3. The network connection control device according to claim 2, wherein the terminal failure release instruction command is transmitted to the second network by a simultaneous broadcast that does not require a confirmation response.