JP3114219B2 - Network connection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-network connecting device for connecting a plurality of local communication networks such as a LAN and a home bus to realize inter-network communication.

[0002]

2. Description of the Related Art A conventional inter-network connection apparatus and inter-network communication system for performing inter-network communication will be described with reference to FIGS.

FIG. 11 shows an example of the configuration of a system to which the inter-network communication device of the present invention is applied. In the figure, an inter-network connection device (100, 101) can connect any communication networks. FIG. 12 is a block diagram showing a configuration example of a conventional network connection device. Communication network connection terminals (115, 116, 117) for connecting to a communication network; a message transmission / reception processing unit (111) for sending and receiving messages; a memory (113) containing address information and relative position information; It comprises an information input / output processing unit (112) for performing registration and search.

[0004] Considering a case where an arbitrary terminal Xn (106) and Yn (108) connected to a communication network as shown in Fig. 11 perform communication, the terminals Xn (106) and Yn (10) are connected.
Since there are a plurality of communication paths during 8), the transmitted message may arrive at the transmission destination in a multiplex manner. Conventionally, as one method of avoiding this, there is a method of configuring a logical tree structure in a communication network so that only one communication path exists between any two terminals. This can be realized by logically disconnecting the connection between a certain network connection device and a certain communication network.

This method will be described with reference to FIG. FIG.
In 3, the network connection device sends a special message (122) called HELLO to the communication network connected thereto. The HELLO telegram includes a number indicating the priority of each inter-network connecting device. Then, each inter-network connecting device transmits the HELLO sent by the inter-network connecting device having a higher priority than itself.
After receiving the message from a certain communication network,
Only when a HELLO message is received from a high-priority inter-network connection device, it transmits its own HELLO message to a communication network other than the communication network that received the HELLO message. In other words, in FIG.
This shows a situation in which an LLO message is being transmitted. For example, once the network connection device 1 (121) receives a HELLO (0) message from the communication network 4 (126), the network connection device 1 (121) ) Is HELLO to communication network 4 (126).
(1) No message is sent, and H is sent from communication network 4 (126).
HELLO (0) only when a message is received
(1) Send a message to the communication network 2 (127).

[0006] Also, among the inter-network connection devices that have received a HELLO message transmitted from two or more communication networks transmitted by the inter-network connection device having a higher priority than the self, the inter-network connection device having the highest priority among them exists. By logically disconnecting the connection with the communication network other than the communication network on the side, a loop in the communication network is logically removed, and a logical tree structure is formed in the communication network.

FIG. 15 shows the algorithm described above.
14 illustrates a tree structure configured in the communication network of FIG. In FIG. 15, the network connection devices 4 (144), 5 (14
5) has disconnected the logical connection with the communication network 5 (150).

Once the tree structure as shown in FIG. 15 is constructed, the network connection device looks at the address of the message sent by the terminal and forms a table for message forwarding in an internal memory. FIG. 14 shows a network connection device (13
0, 131) shows an example of a table configured in the internal memory (135, 136). When receiving the message, the network connection device registers the source address of the message in the address information, and registers the number corresponding to the communication network that received the message in the relative position information. Here, the communication network 1 (132) and the communication network 2 (13
3), numbers corresponding to the communication network 3 (134) are 1, 2, and 3, respectively. During the learning period until the table is constructed, the network connection device must send the received message to all communication networks other than the received communication network. However, once the table as shown in FIG. 14 is completed,
For example, a message addressed to terminal X (137) sent from terminal Y (138) is transmitted to communication network 1 by inter-network connection device 1 (130).
Although the packet is forwarded to (132), it is not forwarded to the communication network 3 (134) by the network connection device 2 (131).

The network connection apparatus 0 (120) shown in FIG. 13 is periodically arranged so that a new tree structure can be reconstructed even when the connection and disconnection of the network connection apparatus are performed and the topology of the communication network changes. The HELLO (0) message (122, 123) is transmitted.

[0010]

Problems to be solved when a conventional network connection device as shown in FIGS. 12 to 15 is used will be described with reference to FIG.

A conventional network connection device transmits and receives a special message to and from a neighboring network connection device to form a logical tree structure in a communication network. However, the tree structure configured in the communication network is configured based on priority information assigned to the inter-network connecting device itself in advance, and at the same time, only one logical tree structure is configured.
Therefore, for example, in the case where a tree structure is configured as shown in FIG. 15, considering the message from the terminal Z (152) to the terminal Y (151), despite the existence of the network connection device 4 (144), The message is transmitted through the communication network 5 (150) as shown.
From the network connection device 3 (143), the communication network 1 (146),
It must be forwarded on the route of the network connection device 0 (140), the communication network 4 (149), the network connection device 1 (141), and the communication network 2 (147). As a result, traffic of communication networks other than the communication network to which the terminals Y (151) and Z (152) are connected increases, and transmission delay in the communication network increases.

The present invention pays attention to this problem, constructs a plurality of logical tree structures in a communication network at the same time, and a message transmitted from each terminal is forwarded to a target terminal under an appropriate tree in the tree. Inter-network connection device that can reduce the increase in traffic and the increase in transmission delay that occur in a communication network due to inter-network communication. It is an object to provide a communication system.

[0013]

According to the present invention, in order to solve the above-mentioned problems, a counter information area is added in a conventional network connection device memory, and a network relating to each communication network connection terminal is used instead of relative position information. Provide connection information. Further, an optimum route generation processing unit for analyzing a logical connection condition with the communication network is provided. Then, when the message transmission / reception processing unit receives the first special message including the address information and the counter information, each processing unit in the apparatus is configured to operate as follows. (1) When the message transmission / reception processing unit receives the first special message from the first communication network connection terminal, the optimum route generation processing unit sends the address information included in the received message via the information input / output processing unit. If the message is not registered, the message transmission / reception processing unit constructs a special message in which only the counter information of the received first special message is increased, and performs communication other than the first communication network connection terminal. The information is sent to the network connection terminal, and the optimum route generation processing unit receives the address information and the counter information of the transmission message via the information input / output processing unit. For the network connection terminal, the network connection information set to 1 is registered in the memory, while if registered, the counter information of the received first special message and the network information registered in the memory are registered. Corresponding mosquito If the former is less than or equal to the latter, the optimum route generation processing unit sets the network connection information corresponding to the first communication network connection terminal to 0 via the information input / output processing unit, and otherwise does not. In this case, the message transmission / reception processing unit is configured to configure a special message in which the counter information of the received message is changed to the registered counter information and transmit the special message to the first communication network connection terminal.

Thereafter, when the message transmission / reception processing unit receives the normal message from the second communication network connection terminal, the information input / output processing unit searches the memory for network connection information corresponding to the destination address of the received message. Only when 1 is registered for the second communication network connection terminal and 2 is registered for the third communication network connection terminal, the message transmission / reception processing unit performs the second communication network connection A message received from the terminal is transmitted to the third communication network connection terminal. (2) In the configuration of the above (1), when the message transmission / reception processing unit receives the normal message and the destination address is not registered in the memory, the message transmission / reception processing unit adds the first special message to the received message. A message to which a return request is added is formed, and the message is sent to a communication network connection terminal other than the communication network connection terminal that received the message. (3) In the configuration of the above (2), a timer for measuring a message reception interval is provided, and the message transmission / reception processing unit periodically connects the second special message including information for identifying itself to another network. It is configured to be transmitted to the device.

[0015] When the timer detects that the second special message transmitted by the certain network connection device has not been received for a predetermined time or more, it notifies the information input / output processing unit and receives the notification. The information input / output processing unit is configured to delete all the contents of the memory. (4) In the configuration of (1) or (2), a timer for measuring a message receiving interval is provided, and the memory is configured to include path record information.

When the message transmission / reception processing unit receives the first special message including the address information, the counter information, and the route record information, the information input / output processing unit also registers the route record information of the received message in the memory, and The transmission / reception processing unit is configured to transmit a first special message in which information for identifying itself is added to the route record information of the received message.

The message transmission / reception processor is configured to periodically transmit a second special message including information for identifying itself to another network connection device.

When the timer detects that the second special message transmitted by the first network connection device has not been received for a certain period of time or more, the timer notifies the optimum route generation processing unit of the second special message. The received optimum route generation processing unit searches the memory via the information input / output processing unit, and detects the network connection information of each communication network connection terminal corresponding to a certain address information and the first special information received from the communication network connection terminal. It is configured to check the route record information of the message.

As a result, if the first network connection device is specified in the route record information corresponding to the fourth communication network connection terminal whose network connection information is registered as 0, the network connection information is set to It changes from 0 to 1 and searches for the route record information corresponding to the communication network connection terminal in which 2 is registered in the network connection information, and the message transmission / reception processing unit checks the address information, the route record information, A first special message including the counter information registered correspondingly is formed and transmitted to the fourth communication network.

Alternatively, as a result of the above investigation, if the first network connection device is specified in the route record information corresponding to the fifth communication network connection terminal whose network connection information is registered as 2, The network connection information is changed from 2 to 0, one of the communication network connection terminals in which 0 is registered in the network connection information is selected, the network connection information is changed from 0 to 2, and the corresponding route record information is changed. And the message transmission / reception processing unit forms a first special message including the address information, the route record information, and the counter information registered corresponding to the address information, the fifth communication network To be sent to (5) It is composed of the inter-network connecting device of (1), (2), (3) and (4), a communication network interconnected by the inter-network connecting device, and a terminal device connected to the communication network. In an inter-network communication system, a terminal device sets its own address in address information and an arbitrary value in counter information when connected to a communication network, after moving within the communication network, or periodically. A first special message is formed and sent to a connected communication network.

[0021]

The present invention has the following functions by the above configuration. (1) The counter information included in the first special message transmitted by each terminal is incremented each time it passes through the network connection device, and the counter information registered in the memory in each network connection device is: It is associated with the distance to the corresponding terminal. Therefore, the network connection device considers that there is a terminal that has transmitted the first special message on the side of the communication network connection terminal that has received the message (sets 2 in the network connection information), The connection terminal is considered to be on the branch side of the tree structure with respect to the communication network connection terminal (1 is set in the network connection information). When the first special message having a value equal to or less than the registered counter information is received from the communication network connection terminal considered as a branch of the tree structure, the connection between the two communication network connection terminals is released. (Set 0 to the branch-side network connection information)
This removes one loop completed by me.

For the above reason, the network connection device transmits the normal message received from the communication network connection device having the network connection information of 1,
By forwarding to the communication network connection terminal whose network connection information is 2, it becomes possible to make the message reach the destination.

Further, the network connection apparatus does not forward a normal message received from a communication network connection terminal whose network connection information is 0 to other communication network connection terminals, so that the message is duplicated on multiple paths. Arriving at the destination.

Further, since the tree structure for a certain terminal is constructed based on the first special message sent by the terminal,
The constructed tree has a radial structure with each terminal as a root. In other words, the route of a message from a certain communication network to a certain terminal is in principle close to the route that can be reached in the shortest time, and the increase in traffic and the increase in transmission delay caused by inter-network communication is reduced. It is possible to do. (2) The network connection device forwards a normal message addressed to an address not registered in the memory to another communication network connection terminal for the time being, and adds a first special message return request to the message. As a result, since the terminal receiving the message transmits the first special message, the tree structure for each terminal can be sequentially reconfigured even when a new interworking device is inserted into the communication network. It becomes possible. (3) The network connection device periodically sends a second special message including information for identifying itself to another network connection device, and the second special message from a certain network connection device is transmitted by a timer. When it is detected that the special message has not been received for a certain period of time, all the contents of its own memory are deleted. As a result, since the network connection device constructs a new table in the memory for the reason described in the above operation (2), if a certain network connection device in the communication network fails or is removed, the topology of the communication network is changed. Even if it changes, the tree structure in the communication network can be reconfigured. (4) route record information is included in the first special message,
When the network connection device registers the route record information of the first special message received from each communication network connection terminal in the memory, and conversely transmits a message at each communication network connection terminal from the information, It is possible to know which inter-network connecting device arrives at the transmission destination.

When a network connection device constituting a tree structure fails or is removed, a physical loop exists in the communication network so that a new tree structure including the entire communication network can be reconfigured again. Is a necessary condition.

Accordingly, the first special message received from the communication network connection terminal side that cuts the loop with the network connection information set to 0, and the removed inter-network connecting device is registered in the route record information. In this case, by sending the first special message to the communication network connection terminal side, it is possible to reconfigure the branch cut from the tree structure to the network connection device and thereafter. Alternatively, even when the removed inter-network connecting device is registered in the route record information corresponding to the communication network connection terminal for which the network connection information is registered as 2, the first communication network connection terminal is provided on the communication network connection terminal side. By transmitting the special message, the branch cut from the tree structure can be reconfigured in the network connection device and thereafter.

The reason is that the above-described configuration realizes the following idea. A point, B point,
It is assumed that points C and D exist in this order, and the loop is cut at point C in order to construct a tree structure with point A as a root. As a result, a branch called ABC and a branch called ADC are formed. Thereafter, if the loop is cut at the point B for some reason, the BC section is separated from the configured tree structure. At this time, the point C notices the abnormality at the point B, and the loop connection is performed again, so that a new tree structure including the branches ADB and AB is reconstructed. . The configuration of the network connection device described above realizes the operation at point C in this example.

In this case, instead of reconstructing the entire tree structure, only the branch portions cut from the tree structure by removing the inter-network connecting device are reconstructed. Necessary traffic and time required for reconfiguration can be reduced.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An inter-network connection device according to the present invention will be described with reference to FIGS.

FIG. 1 is a block diagram showing an example of the configuration of an internetwork connecting apparatus according to the present invention. Communication network connection terminals (15, 16, 17) for connecting to a communication network; a message transmission / reception processing unit (11) for sending and receiving messages; a timer (14) for measuring a received message interval; address information and counter information; A memory (13) containing connection information and route record information; an information input / output processing unit (1) for registering and retrieving information in this memory;
2) It comprises an optimum route generation processing unit (18) for analyzing the logical connection condition with the communication network. Compared with the conventional network connection apparatus shown in FIG. 12, counter information is added in a memory, and network connection information and route record information are registered instead of relative position information. Further, the configuration is such that a timer (14) and an optimum route generation processing unit (18) are added.

Here, the role of each of the above components will be described with reference to the first embodiment of the present invention shown in FIG.

FIG. 2 shows a communication network 1 (211) and a communication network 2 (2
12), the communication network 3 (213), the communication network 4 (214), and the communication network 5 (215) are the network connection device 0 (200), the network connection device 1 (201), and the network connection device 2 (202). An example is shown in which interconnection is established by an inter-network connection device 3 (203), an inter-network connection device 4 (204), and an inter-network connection device 5 (205). Here, an example is considered in which all the network connection apparatuses have two communication network connection terminals P and Q. The terminal X (216) is connected to the communication network 4, and the terminal Y (217) is connected to the communication network 2.
However, a terminal Z (218) is connected to the communication network 5.
The configuration of the topology composed of the inter-network connection device and the communication network, and the connection communication network of the terminals Y and Z are the same as those shown in FIG.
Exactly the same as 5.

Here, a first special message whose address information is SA and counter information is HC is represented by ID (SA, HC). In the figure, the terminal X (216) stores its own address information and counter information. An example is shown in which the above-mentioned special message with information is transmitted to a communication network.

Node in the network connection device memory indicates address information, VHC indicates counter information, and Port and FW indicate network connection information. Here, it is promised that the contents of the memory be described by M (Node, Port, VHC, FW).

Now, when each terminal is connected to the communication network,
The above-mentioned special message in which the counter information HC is set to 0, ID
(SA, 0) is transmitted to the communication network. Then, each network connection device executes the following algorithm.

Step 1. When ID (X, i) is received from terminal A, M (X, A, i + 1, 1) is registered in the memory.

Step 2. Send ID (X, i + 1) to terminal B. Step3. Then, perform one of the following operations.

Case 1. If the first special message whose address information is X is not received from the terminal B for a fixed time, nothing is performed.

Case 2. ID (X, j) is received from terminal B, and if VHC = i + 1 ≧ j, the memory content is changed to M
Update to (X, A, i + 1,0).

Case 3. ID (X, j) is received from terminal B, and if VHC = i + 1 <j, ID is
Retransmit (X, i + 1).

However, the above algorithm shows an algorithm when the network connection device receives a special message having address information X not registered in the memory for the first time.

FIG. 2 shows that when terminal X (216) is connected to the communication network, ID (X, 0) is sent out to communication network 4 (214), and network connection device 0 (200), network connection device 1 (20
1), the network connection device 2 (202) is Q, Q, P
This is received from the terminal, the contents of the memory are registered in accordance with the above algorithm, and the ID (X, 1) is transmitted from the P, P, and Q terminals, respectively, and further received by another network connecting device. In other words, all network connection devices are I
This shows an example in the case where D (X, HC) is received and the above algorithm is executed. In the figure, the network connection device 3 (203), the network connection device 4 (204), and the network connection device 5 (205) have the ID (X , 2) is transmitted.

FIG. 2 further shows a terminal Y (21)
7) When the terminal Z (218) is connected to the communication network, it sends ID (Y, 0) and ID (Z, 0), respectively. 9 shows an example of a result obtained when registration is performed.

Here, the network connection device is a terminal X (216),
When a normal message is received from Y (217) and Z (218), the message is forwarded by the following algorithm.

Step 1. When a message whose transmission destination address is X is received from the terminal A, the value of Port and FW registered in correspondence with Node = X in the memory, Port
(X) and FW (X) are searched.

Step 2. One of the following operations is performed according to the search result. Case1. If Port (X) = A, the received message is discarded.

Case2. Port (X) = B and FW
If (X) = 0, the received message is discarded.

Case3. Port (X) = B, and F
If W (X) = 1, the received message is forwarded to terminal B.

When each inter-network connection device operates as described above, when a terminal connected to each communication network sends out a message addressed to terminals X, Y, and Z, the route through which the message FIG. 3 shows whether or not the vehicle arrives.

FIG. 3A shows a route in which a message addressed to terminal X is forwarded, FIG. 3B shows a route in which a message addressed to terminal Y is forwarded, and FIG. 3C shows a route in which a message addressed to terminal Z is forwarded. Shows the route to be taken. Both figures show that the message is forwarded on one tree structure configured in the communication network. Also, the message forwarding operation of the network connection device is unidirectional as is clear from the above-described algorithm, and in the figure, each network connection device forwards a message only to a tree-structured route, that is, a destination terminal direction. .

In the conventional example shown in FIG. 15, terminal Z (15
Although the message from 2) to the terminal Y (151) had to be forwarded along the route as shown, according to the present invention, as shown in FIG. 3B, the communication network 5 (34)
Terminal Y (3) transmitted by the terminal Z (33) connected to
The message addressed to 2) can reach the destination only by forwarding by the internetwork connecting device 4 (35). That is, in this case, no inter-network communication message is generated except for the communication network 5 (34) and the communication network 2 (36), and it is possible to arrive at the destination via the shortest route.

In the first embodiment shown in FIG. 2, the address information is represented by Node, the counter information is represented by VHC, and the network connection information is represented by Port and FW in the network connection device memory. This is a configuration of the memory in the form shown in FIG. That is, when the network connection device has only two communication network connection terminals P and Q as in the first embodiment, the first special message having certain address information is received first. This means that the network connection information can be managed only by the numbers of the communication network connection terminals and the binary network connection information (0 or 1, whether or not to forward) regarding the other communication network connection terminals. This memory is shown in FIG.
A configuration as shown in FIG. This means that, for the first special message having certain address information, the value 2 is assigned to the communication network connection terminal received first, and the value 0 or 1 is assigned to the other communication network connection terminals. To manage. When the network connection device has a plurality of communication network connection terminals, a memory can be configured as shown in FIG.

Although FIGS. 3 and 4 have been described using the values 0, 1, and 2 as the values of the network connection information, the same effect can be obtained by arbitrarily setting the values as long as they can be distinguished.

The algorithm in the case where the network connection device has three or more communication network connection terminals and receives a special message is as follows. However, in the network connection device memory, the address information is managed by Node, the counter information is managed by VHC, and the network connection information is managed by FW (communication network connection terminal number).
(Node, VHC, FW (communication network connection terminal number)).

Step 1. When ID (X, i) is received from terminal k, M (X, k, i + 1, FW (k) =
2, FW (other than k) = 1) is registered.

Step 2. In addition to terminal k, ID (X, i +
Send out 1). Step3. Then, perform one of the following operations.

Case 1. If no first special message whose address information is X is received for a fixed time from a terminal other than the terminal k, nothing is performed.

Case 2. When ID (X, j) is received from the terminal m and VHC = i + 1 ≧ j, the memory content is changed to M
(X, k, i + 1, FW (m) = 0, FW (other than m) =
(No change).

Case3. ID (X, j) is received from terminal m, and if VHC = i + 1 <j, ID
Retransmit (X, i + 1).

However, the above algorithm shows the algorithm when the network connection device receives a special message having address information X not registered in the memory for the first time.

When a network connection device having three or more communication network connection terminals receives a normal message next time, it forwards the message according to the following algorithm.

Step 1. When a message whose destination address is X is received from the terminal k, the FW value and FW (X, communication network connection terminal number) registered corresponding to Node = X in the memory are searched. I do.

Step 2. One of the following operations is performed according to the search result. Case1. If FW (X, k) = 2, the received message is discarded.

Case2. If FW (X, k) = 0, the received message is discarded. Case3. If FW (X, k) = 1, FW (m) = 2
The received message is forwarded to the communication network connection terminal m.

In the above example, the network connection device is described as an example in which the counter information of the received first special message is incremented by one, but the increment value of the counter value differs depending on each network connection device. Has the same effect.
The same effect is obtained even when each terminal sends a special message in which the counter value is set to a value other than 0. Further, the same effect can be obtained even if the all-network connection device decreases the counter value of the received special message.

Next, a second embodiment will be described. In the first embodiment, when a terminal is first connected to a communication network,
First, each terminal includes its own address information and counter information
An example is shown in which the network connection device registers information in an internal memory based on this information. However, even when the terminal moves within the communication network, if the first special message transmitted after the movement and the first special message transmitted last time and this time can be distinguished, the information in the memory can be re-registered. . For example, each terminal includes the second counter information in the first special message, and each terminal transmits the second special information every time the first special message is transmitted.
In the meantime, the network connection device also registers the second counter information in the memory, and when the second counter information receives the first special message that is different from the last time, the first embodiment The same processing as described above is performed to re-register the memory contents.

Next, a third embodiment will be described. Since the network connection apparatus has a timer therein, the elapsed time from the reception of the most recent first special message having the address information is measured for the first special message having each address information. . Then, the first special message received after a lapse of a predetermined time or more from the previous reception is determined to be different from the last special message, and the same processing as described in the first embodiment is performed, and the contents of the memory are read. Re-register.

Next, a fourth embodiment will be described. Each terminal connected to the communication network periodically sends a first special message to the communication network by using the method in the second embodiment or the third embodiment. When each terminal moves within the communication network, the network connection device can not only re-register the memory, but also when the network connection device fails or is disconnected from the communication network, the network connection device can store the memory. You can re-register. In addition, since the tree structure is periodically reconfigured, there is a high probability that a message is always forwarded through an optimal route with the least traffic.

Next, a fifth embodiment will be described. The network connection device receives a normal message, searches the memory for the transmission destination address, and if this is not registered in the address information in the memory, the communication network connection terminal other than the communication network connection terminal that has been received for the time being. At this time, a message in which the first special message return request is added to the received message is transmitted. As a result, the terminal that has received the telegram arriving at the destination immediately composes the first special telegram and sends it to the communication network, so that the terminal that has not been registered in the network connection device is newly registered in the memory. It is possible to do. Therefore, even when a new network connection device is connected between communication networks, information can be registered in the memory in the network connection device. The present embodiment is also effective when there is a limit on the memory capacity in the network connection device, and only the terminal that has recently been engaged in communication is registered in the memory, and the rest is deleted from the memory contents. It becomes.

Next, a sixth embodiment will be described. In the fourth embodiment, when the number of terminals increases, the traffic of the first special message increases. This embodiment solves this problem. Under the fifth embodiment, the network connection apparatus periodically transmits a second special message including information specifying itself, for example, address information of the network connection apparatus, to another network connection apparatus. Send out. The inter-network device recognizes that the second special message transmitted by the other inter-network device is periodically received, and the inter-network device that has transmitted the second special message operates normally without failure. Judge that there is. When the timer in the network connection device detects that the second special message from the specific network connection device is no longer received, it is interpreted that the network connection device has failed or has been removed from the communication network. I do. In this case, since each network connection device must re-register the information in the memory, the network connection device deletes all the memory contents. Thereafter, all the normal messages received by the network connection device are processed by the algorithm shown in the fifth embodiment. As a result, when the topology changes, each network connection device re-registers the memory contents. It becomes possible to go. In this case, unlike the fourth embodiment, the message required to detect the topology change is not the first special message sent by each terminal,
Since this is the second special message transmitted by the network connection device, the traffic for monitoring the topology change does not increase even when the number of terminals increases.

Next, the seventh embodiment will be described with reference to FIGS.
This will be described with reference to FIG. The configuration in FIG. 5 is completely the same as the configuration in FIG. 2 used for describing the first embodiment. This time, the route record information is included in the first special message. When each terminal sends the first special message, nothing is included in the route record information. Then, when each network connection device handles the first special message by the above-described algorithm and increases the counter information of the received special message and sends it out, it adds information specifying itself to the route record information and transmits it. . In FIG. 5, the network connection device B0 (500) and the network connection device B1 (50)
1), network connection device B2 (502), network connection device B3
(503), the network connection device B4 (504), and the network connection device B5 (505) are B0, B1, B2, and B, respectively.
3, B4, and B5 are added to the route record information.

FIG. 5 shows an example in which the network connection device registers information in the memory under exactly the same conditions as in FIG. What is different from FIG. 2 is that the in-memory table is created separately for the case where the communication network connection information is FW = 1 and FW = 0,
Only when FW = 0, the route record information included in the special message received from both the P and Q terminals is registered. The route record information portion is a flag in which a flag 1 is set for one of B0 to B5 included in the first special message.

Here, the first special message in which the address information is SA, the counter information is HC, and the route record information is B is represented by ID (SA, HC, B).

In the memory of the network connection device, Node represents address information, VHC represents counter information, Port and FW represent network connection information, B0 to B5 represent route record information, and the contents of the memory are represented by M (FW , Node, VHC (Node, Port),
Bm (Node, Port)).
m takes a value from 0 to 5.

Further, also in this embodiment, each inter-network connecting device periodically sends the second special message described in the sixth embodiment to another inter-network connecting device. When the timer in the network connection apparatus detects that the second special message from the specific network connection apparatus Bk is no longer received, the following algorithm is executed.

Step 1. All registered address information A
, The value of the network connection information FW, FW (A), the value of the route record information Bk, and Bk (A, Port) are searched.

Step 2. FW (A) = 0 and Bk
(A, P) If there is no terminal of the address A where XOR Bk (A, Q) = 1, nothing is performed. If any, Step3.
Go to XOR is an exclusive OR.

Step 3. One of the following operations is performed depending on the conditions. Case1. If Bk (A, P) = 1, M (0, A, V)
HC (A, Port), Bm (A, Port))
(1, A, VHC (A, Q)), and a first special message, ID (A, VHC (A, Q,
Q), Bm (A, Q)).

Case2. If Bk (A, Q) = 1, M
(0, A, VHC (A, Port), Bm (A, Por
t)) is rewritten to M (1, A, VHC (A, P)),
A first special message, ID (A, VHC) is connected to the communication network connection terminal Q.
(A, P), Bm (A, P)).

FIG. 6 is a block diagram of the network connection device B4 shown in FIG.
This is an example of a case where each network connection device operates according to the above algorithm when (504) is removed. By executing the above algorithm, the network connection device 1B (521), the network connection device B2 (522), and the network connection device B3 (523) change the first special message (534),
(535) and (536) are transferred to the communication network 2 (52
7), to the communication network 3 (528) and the communication network 5 (530). In FIG. 6, the above algorithm distinguishes the first special message sent from the network connection device from the first special message sent by each terminal.
It is expressed by

Thereafter, since the pID message is handled in the same manner as the normal first special message ID message, the network connection device B5
Then, the memory is re-registered.

FIGS. 8 (a), 8 (b) and 8 (c) show the lower part of FIG. 6 when a terminal connected to each communication network sends a message addressed to terminals X, Y and Z. It indicates whether the packet arrives at the destination via such a route. 5 is different from the tree structure shown in FIG.
FIG. 9 shows an example of a reconfiguration as shown in FIG. 8 by removing (70).

FIG. 6 shows the state of FIG.
(504) is removed, and the network connection apparatus B2 (5
02) and the network connection device B3 (503) transmit the first special message at almost the same time. FIG. 7 shows a case in which the inter-network connecting device B4 (504) is similarly removed from the state of FIG. 5, but in this case, the inter-network connecting device B3 (503) is used by the inter-network connecting device B2 (502).
However, this shows an example in which the first special telegram is transmitted quite early. As a result, the first special message (636) sent by the internetwork connection device B5 (625) has been received before the internetworking device B3 (623) sends out the first special message. Also in this case, each network connection device re-registers the information in the memory by the above algorithm.

FIGS. 9 (a), 9 (b) and 9 (c) show the lower part of FIG. 7 when a terminal connected to each communication network sends a message addressed to terminals X, Y and Z. It indicates whether the packet arrives at the destination via such a route. 5 is different from the tree structure shown in FIG.
FIG. 10 shows an example of a reconfiguration as shown in FIG. 9 by removing (80).

In the seventh embodiment shown in FIGS. 5 to 7,
The network connection device manages information in a memory with the configuration shown in FIG. This is a configuration in the case where the network connection device has only two communication network connection terminals P and Q as in the seventh embodiment, but more generally, FIG.
0 (b) is also possible. FIG. 10C shows a configuration example of a memory in a case where the network connection device has three or more communication network connection terminals.

In FIG. 10, the value of the network connection information is 0,
Although 1 and 2 are used, any value can have the same effect as long as they can be distinguished. In any case, if the value of the network connection information is 1, the corresponding counter information and route record information may or may not be registered.

The network connection information determining algorithm when the network connection device has three or more communication network connection terminals is as follows.

Step 1. All registered address information A
, The value of the network connection information FW, FW (A, Por
t), the value of the route record information Bk, Bk (A, Port)
Search for.

Step 2. FW (A, PortC) = 0, Bk (A, PortC) = 1, and FW (A, P
ortD) = 2 and Bk (A, PortD) = 0, M (1, A, VHC (A, PortC), Bm
(A, Port)) is registered, and the ID is
(A, VHC (A, PortD), Bm (A, Port
D)).

Step 3. FW (A, PortC) = 2, Bk (A, PortC) = 1, and FW (A, PortC)
ortD) = 0 and Bk (A, PortD) = 0, M (0, A, VHC (A, PortC), Bm
(A, Port)) and M (2, A, VHC)
(A, PortD), Bm (A, Port)) are registered, and ID (A, VHC (A, Port)
C), Bm (A, PortC)).

[0091]

As described above, according to the network connection apparatus according to the present invention, information that simultaneously forms a plurality of logical tree structures in a communication network to which the network connection apparatus is connected is provided. Built in memory. Therefore, (1) the all-networks connection apparatus has an effect that only one telegram can arrive at the transmission destination only by forwarding the received telegram in accordance with the network connection information in the memory. (2) Each message communicated between networks is forwarded on a radially structured tree structure with the destination terminal as the root, so that the communication path can arrive at the destination in the shortest time in principle It becomes something close to a simple route. Therefore, there is an effect that it is possible to reduce an increase in traffic and an increase in transmission delay caused by the communication between networks. (3) While configuring a logical tree structure in the communication network, at the same time, there is an effect that a relative direction in which each terminal is connected can be learned and a table for message forwarding can be created. (4) A tree structure weighted according to the processing capability of each network connection device by setting the increment value of the counter information associated with the first special message transmission to a different value for each network connection device. Can be configured. (5) The first special message is transmitted even when the terminal moves in the communication network, and each inter-network connection device distinguishes the last and the first special message received this time, so that the tree connection is performed when the terminal moves. This has the effect that the structure can be reconfigured. (6) Since each terminal periodically sends the first special message, the tree structure can be reconfigured even when the network connection device is newly inserted or removed from the communication network. It has the effect of. (7) The network connection device constructs and transmits a message to which a first special message return request is added to a message addressed to an address not registered in the memory, so that the network connection device newly establishes a communication network. Has an effect that the tree structure can be reconstructed even when the tree structure is inserted. (8) By transmitting and receiving a second special message between the network connection devices, detecting that the second special message from the certain network connection device is no longer received, and clearing the internal memory, This has the effect that the tree structure can be reconfigured even when the interconnecting device fails or is removed from the communication network. Also, since the message used for detecting the topology change is the second special message sent by the network connection device, there is an effect that the traffic for monitoring the topology change may be small. (9) By including the route record information in the first special message and registering the route record information in the network connection device memory, even if the network connection device fails or is removed from the communication network, There is an effect that the tree structure can be reconstructed using this path record information. In this case, it is possible to construct a new tree structure as a whole only by reconstructing a part of the tree structure instead of reconstructing the entire tree structure. This has the effect of reducing traffic and the time required for reconfiguration.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration example of an inter-network connection device of the present invention.

FIG. 2 is a diagram for explaining the operation of the network connection apparatus according to the first embodiment;

3A is a diagram showing a communication path of a message addressed to a terminal X in the tree structure configured according to the first embodiment; FIG. (C) is a diagram showing a communication route of a message addressed to the terminal Z as in the above.

FIG. 4A is a diagram showing a first configuration example of an inter-network connection device memory according to the first to sixth embodiments; FIG. 4B is a diagram showing the same as in the second embodiment of the inter-network connection device memory; FIG. 3C is a diagram showing a third configuration example of the memory in the network connection device;

FIG. 5 is a diagram showing a communication network to which a seventh embodiment is applied;

FIG. 6 is a first diagram illustrating the operation of the network connection apparatus in the seventh embodiment;

FIG. 7 is a second diagram illustrating the operation of the network connection apparatus according to the seventh embodiment;

8A is a diagram showing a communication route of a message addressed to a terminal X in the tree structure configured according to FIG. 6 which is the seventh embodiment. FIG. FIG. 3 (c) shows a communication route of a message addressed to terminal Z.

9A is a diagram illustrating a communication path of a message addressed to a terminal X in the tree structure configured according to FIG. 7 according to the seventh embodiment. FIG. FIG. 3 (c) shows a communication route of a message addressed to terminal Z.

FIG. 10A is a diagram showing a first configuration example of a memory in a network connection device according to a seventh embodiment. FIG. 10B is a diagram showing a second configuration example of a memory in the network connection device. FIG. 3C is a diagram showing a third configuration example of the memory in the network connection device;

FIG. 11 is a diagram showing an example of a system to which the network connection device of the present invention is applied;

FIG. 12 is a block diagram showing a configuration example of a conventional network connection device.

FIG. 13 is a first diagram illustrating the operation of a conventional network connection apparatus.

FIG. 14 is a second diagram illustrating the operation of the conventional network connection device.

FIG. 15 is a third diagram for explaining the operation of the conventional network connection device;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Inter-network connection apparatus 11 Message transmission / reception processing unit 12 Information input / output processing unit 13 Memory 14 Timer 15 Communication network connection terminal 16 Communication network connection terminal 17 Communication network connection terminal 18 Optimal route generation processing unit 20 First special telegram 21 First Special message 22 First special message 23 First special message 24 First special message 25 First special message 26 First special message 27 First special message 28 First special message 29 First special message Telegram 30 First special telegram 200 Inter-network connection device 0 201 Inter-network connection device 1 202 Inter-network connection device 2 203 Inter-network connection device 3 204 Inter-network connection device 4 205 Inter-network connection device 5 211 Communication network 1 212 Communication network 2 213 Communication network 3 214 Communication network 4 215 Communication network 5 216 Terminal X 217 Terminal Y 218 Terminal Z 220 Communication network connection terminal P 221 of inter-network connection device 0 Communication network connection terminal Q 222 of network connection device 0 Communication network connection terminal P 223 of network connection device 1 Communication network connection terminal Q 224 of network connection device 1 Communication network connection terminal P 225 of network connection device 2 Communication network connection terminal Q 226 of connection device 2 Communication network connection terminal P 227 of network connection device 3 Communication network connection terminal Q 228 of network connection device 3 Communication network connection terminal P 229 of network connection device 4 Network connection device 4 communication network connection terminal Q 230 communication network connection terminal P 231 of network connection device 5 communication network connection terminal Q 31 terminal X 32 terminal Y 33 terminal Z 34 communication network 535 network connection device 4 36 communication network 2 40 memory 41 memory 42 memory 500 network connection device B0 501 network connection device B1 502 network connection device B2 503 network connection device B3 504 network connection device B4 505 network Connection device B5 506 Communication network 1 507 Communication network 2 508 Communication network 3 509 Communication network 4 510 Communication network 5 511 Terminal X 512 Terminal Y 513 Terminal Z 520 Inter-network connection device B0 521 Inter-network connection device B1 522 Inter-network connection device B2 523 Inter-network connection device B3 524 Inter-network connection device B4 525 Inter-network connection device B5 526 Communication network 1 527 Communication network 2 528 Communication network 3 529 Communication network 4 530 Communication network 5 531 Terminal X 532 Terminal Y 533 Terminal Z 534 First Special message 535 First special message 536 First special message 620 Network connection device B0 621 Network connection device B1 622 Network connection device B2 623 Network connection device B3 624 Network connection device B4 625 Network connection device B5 626 Communication network 1 627 Communication network 2 628 Communication network 3 629 Communication network 4 630 Communication network 631 terminal X 632 terminal Y 633 terminal Z 634 first special telegram 635 first special telegram 636 first special telegram 70 inter-network connection device 4 80 inter-network connection device 4 90 memory 91 memory 92 memory 93 memory 100 inter-network Connection device 1 101 Inter-network connection device M 102 Communication network 1 103 Communication network 2 104 Communication network N 105 Terminal X1 106 Terminal Xn 107 Terminal Y1 108 Terminal Yn 109 Terminal Z1 110 Terminal Zn 111 Message transmission / reception processing unit 112 Information input / output processing unit 113 Memory 115 Communication Network Connection Terminal 116 Communication Network Connection Terminal 117 Communication Network Connection Terminal 118 Network Connection Device 120 Network Connection Device 0 121 Network Connection Device 1 122 HELLO (0) Message 123 HELLO (0) Message 124 HELLO (1 ) Telegram 125 HELLO (1) Telegram 26 communication network 4 127 communication network 2 130 inter-network connection device 1 131 inter-network connection device 2 132 communication network 1 133 communication network 2 134 communication network 3 135 memory 136 memory 137 terminal X 138 terminal Y 139 terminal Z 140 inter-network connection device 0 141 Inter-network connection device 1 142 Inter-network connection device 2 143 Inter-network connection device 3 144 Inter-network connection device 4 145 Inter-network connection device 5 146 Communication network 1 147 Communication network 2 148 Communication network 3 149 Communication network 4 150 Communication network 5 151 Terminal Y 152 Terminal Z

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-34574 (JP, A) JP-A-62-216542 (JP, A) JP-A-63-13544 (JP, A) 158936 (JP, A) JP-A-63-174446 (JP, A) JP-A-63-305638 (JP, A) JP-A-3-38132 (JP, A) JP-A-3-108925 (JP, A) JP-A-3-216040 (JP, A) JP-A-4-3549 (JP, A) IEEE TRANSACTIONS ON CONSUMER ELECTR ONICS, Vol. 37 No. 3, Aug. 1991, I.S. Takashima et al. , "AN EXPAND SPANNING-TREE PROT OCOL FOR HOME-ORIENTED NETWORK MANAGEMENT", pages. 379-387 (58) Fields surveyed (Int. Cl. ⁷ , DB name) H04L 12/46 H04L 12/28 H04L 12/66 INSPEC (DIALOG) JICST file (JOIS)

Claims (6)

(57) [Claims] A plurality of communication network connection terminals for connecting to a communication network; a first special message including address information of the terminal and predetermined counter information transmitted from the terminal; and receiving the counter information. Register a message transmission / reception processing unit for updating and transmitting the first special message, address information of each terminal, counter information indicating a distance to each terminal, and network connection information indicating a logical connection with a communication network. To input and output information for registering and searching information in the memory
And a communication unit that receives the first special message for each of the address information.
Network connection terminal information with predetermined values as network connection information
The communication network connection terminal other than the received communication network connection terminal is set in the memory.
When receiving the first special message, the address of the terminal
Counter information in the memory corresponding to information and the first
Compare the counter information of the special message of
Counter information is equal to or greater than the counter information of the first special message.
In the memory corresponding to the address information of the terminal
Network connection information to the first value indicating the release of the connection,
The counter information in the memory is the counter of the first special message.
If it is smaller than the counter information, the
Update the counter information to the counter information in the memory.
A network connection device comprising: a route generation processing unit . Wherein upon receiving the message to hold the destination address information, the information output processing unit searches the network connection information corresponding to the destination address information from the memory, the optimum route generating process The unit determines that the network connection information is the first
2. The network connection apparatus according to claim 1, wherein the message is discarded if the value is . 3. A message storing address information of a transmission destination.
When receiving, the information input / output processing unit sends the address of the transmission destination from the memory.
Search for network connection information corresponding to the scan information, the optimum route generation processing unit, a communication network receiving the message
Network connection information corresponding to a communication network connection terminal different from the connection terminal
Is not the first value, the message is sent to the different communication network connection terminal.
Interworking unit according to claim 1 or claim 2, wherein sending the. 4. The method according to claim 1, wherein :
Network connection corresponding to the communication network connection terminal that received the special message
Information to a second value, other than the received communication network connection terminal
The corresponding network connection information is set to a third value, and the first special
The sentence counter information corresponds to the received network connection terminal.
The communication network connection is performed when the value is equal to or less than the counter information in the memory.
When the network connection information corresponding to the connection terminal is updated to the first value and a message holding the destination address information is received,
The network connection information corresponding to the received communication network connection terminal is the third
If the value is a value, the network connection information whose network connection information is the second value
3. The method according to claim 1, wherein the data is transmitted to a child.
The placing of the interworking unit. 5. The message transmission / reception processing unit receives the first special message.
Information that specifies the network connection device is used as route record information in the message.
To the first special message and send the information,
The processing unit includes the path included in the received first special message.
2. The recording information is registered in a memory.
The inter-network connection device according to claim 1. 6. A plurality of communication networks for connecting to a communication network.
A connection terminal, the terminal address information transmitted from the terminal, and a predetermined
Receiving a first special message including counter information,
Message transmission for updating information and transmitting the first special message
A reception processing unit, address information of each terminal, and a cowl indicating the distance to each terminal.
Network information, which indicates logical connection with the communication network.
A memory for recording the first special message for each address information.
Network connection terminal information and the received communication network connection terminal
Information on external communication network connection terminals and the information registered in the memory.
Receiving the first special message having a value equal to or less than the counter information
Network connection terminal information and the specified value
An optimal route generation processing unit to be set as connection information; and an information processing unit that stores information of the first special message and registration information in the memory.
The address information of the memory and the counter information.
Information and an information input / output processing unit for updating the network connection information.
If the network connection information corresponding to the transmission destination address information of the message received from the communication network connection terminal is not registered in the memory, the message transmission / reception processing unit adds a request to return the first special message to the received message. Then, the information is transmitted to a communication network connection terminal different from the received communication network connection terminal, and the terminal corresponding to the destination address information transmits the first special message at the time of receiving the added message, whereby the information is stored in the memory. An inter-network connection device that performs registration.