JPH06318950A - Control system for tree structure network - Google Patents

Abstract

PURPOSE:To select and designate nodes which should be excluded from application in the case of distribution dependent upon broadcasting by providing a management node with a resource distributing means which distributes information including resources and a list of nodes, which should be excluded from application, by broadcasting. CONSTITUTION:A management node 1 designates node names of excepted nodes excluded from application because of execution of maintenance or the like and designates resource names of resources to be applied (to be executed). A resource distributing means 1a stores excepted node names in an exception list 2c of a disk 2 and distributes information including the exception list 2c and designated resource names to nodes 3 just under the node 1. In each node 3, information is received to start a distribution discriminating relay means 3a, and it is discriminated whether the node name of the node 3 itself is included in the exception list in reception information or not. If it is not included, designated resources are applied in the node 3 itself; but if it is included, the application processing is not executed, and information is distributed to nodes 5 just under the node 3 itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tree structure network control system. A tree-structured network is known as one of network structures. This tree structure network is a management method in which a large number of nodes have a tree structure relationship, and lower nodes are managed only by directly connected upper nodes. For this reason, there is an inconvenience that it is impossible to redistribute only to a node that has been unsuccessful at the time of distributing information to all nodes, or to not distribute to a node that does not need to distribute.

[0002]

2. Description of the Related Art FIG. 10 is an explanatory view of a conventional example. Figure 10
In the tree structure network shown in FIG. 1, a node R (referred to as a root), which is a management center of the network, is provided at the top of the tree structure, and a node A is subordinate to the node R.
And node B are arranged, and node C, node D, and node E are arranged below node A, the nodes are connected by a communication line, and each node has a device having an information processing function ( It consists of a personal computer, workstation, terminal device, etc.).

This tree structure network is composed of a large number of nodes, and may be composed of 100 or more nodes, and the number of layers of the tree changes in accordance with the number of nodes.

Disks (including hard disks and flexible disks) Fr and F that constitute a file system are respectively provided in the nodes R, A, B ...
a, Fb, Fc ... are respectively provided (Fb, Fc
.. is not shown), disk Fr of root (node R)
Contains the resources (files of various commands, data, programs, etc.) provided only in the management center, and the node name management list (node names in the example in the figure) that directly stores the node names directly under itself in the tree structure. It is composed of A and B). Among the lower nodes of the root node R, the disk of the intermediate node (the node on which the lower node is located) is the disk (the disk Fa of the node A in the example in the figure)
Is provided with a direct node name management list (resources for nodes (not shown) are also stored).
In this example, the node names of node C, node D, and node E are stored.

In this tree structure network, an operating terminal equipped with a display and a keyboard provided at the root (node R) broadcasts a resource designation (representing the processing content to be executed) to all lower nodes. , The processing contents instructed from the root can be executed all at once in all nodes. In this case, all "resources" are indicated by a disk, represent commands, data, programs, etc., and execute the same processing at the same time for each node below the root, such as modifying programs and data. Let

Resources (disks representing commands, programs, etc.) representing the contents to be executed in the other nodes are designated from the input / output device equipped with the display and keyboard provided at the root (node R), When a distribution instruction is given, the distribution function of the root (node R) automatically refers to the management list directly under the disk Fr, and the node A,
Data representing the designated resource is transmitted to the node B via the communication line. Upon receiving this resource, the node A applies (executes) the resource in its own node, and also refers to the disk Fa and refers to each node C, D, E stored in the node name management list directly under it. Distribute (send) the instructions received from each route as they are
To do. When each of the nodes C to E receives the resource transmitted from the node A, which is an upper node, each node applies (executes) the resource by itself.

In such a tree structure network, since each node manages only the node directly under itself, it is possible to newly add or delete a node or leaf (the lowest node) to a lower node. However, management is easy because it can be dealt with only by modifying the node name management list directly under the disk of the upper node.

[0008]

The above conventional tree structure network has the following problems. If a transmission error occurs during distribution in the network, the cause must be removed by manpower, etc., and then retransmitted from the root (node R). It is not delivered to each node below the road). However, when the error occurs, it is not possible for the root node to know which route it is on, so it must be broadcast again to all nodes.

There is a case in which it is desired to exclude only the designated node or leaf (the lowest node) from the lower nodes due to maintenance (fault repair, device replacement, etc.). However, even in such a case, there is no way to specify the nodes to be excluded. As a method of coping with this, it is necessary to perform an operation of providing a process for stopping the application of the resource received by each node to the excluded node or leaf. However, since this operation needs to be performed individually at each node, it takes time and effort.

According to the present invention, in the case of broadcast distribution, it is possible to select and specify nodes to be excluded from application, and when an error occurs, remove the cause of the error and then deliver the error without performing complicated processing. It is an object of the present invention to provide a control method of a tree structure network that can be delivered only to nodes that have not received the data.

[0011]

FIG. 1 is a block diagram showing the principle of the present invention. In FIG. 1, 1 is a management node (root),
2 is a disk provided in the management node, 3 is a lower node (node name is A, B) of the management node, 4 is a disk provided in the node 3, 5 is a lower node of the node 3 (node A) (Node name is C, etc.), 6 is a disk provided in the node 5, and a node exists below the node 5.

In the management node 1, 1a is a resource delivery means including an exclusion list, 1b is a non-delivery information receiving means, and 1c is a retransmission information delivery means. In the node 3, 3a is a delivery discrimination relay means, 3b is a non-delivery information creating / relaying means, 3c.
Is a retransmit information discrimination / relay means. Further, 5a to 5c provided inside the node 5 are each means 3 in the node 3.
It is the same means as a to 3c, 5a is a delivery discrimination relay means, 5b is a non-delivery information preparation / relay means, and 5c is a retransmission information discrimination / relay means.

In addition, 2 in the disk 2 of the management node 1
a is a resource, 2b is a direct node management list, 2c is an exclusion list indicating nodes to which application is excluded, and 2d is non-delivery information. Further, 4a and 6a in the disks 4 and 6 of the nodes 3 and 5 are the direct node management list.

According to the present invention, when a list of nodes to which the application is excluded is also designated at the time of distributing resources from the management node, it is determined whether or not the own node is included in the exclusion list at each node to which the distribution is applied. Relays the received resource without applying it to the local node. In addition, if it is found that the delivery is undeliverable due to a failure, etc., non-delivery information is generated for the upper node, and the node name is added and transmitted. When receiving and sending retransmission information, if the received non-delivery information is added and sent, the node on the way is not applied and the node below the node that generated the non-delivery information receives and applies it.

[0015]

In the management node 1, when an exclusion node name to be excluded due to maintenance or the like is specified and a resource name to be applied (desired to be executed) is specified, the resource distribution means 1
a is activated. The resource distribution unit 1a stores the excluded node name in the excluded list 2c of the disk 2, and the direct subordinate node of its own node is the direct subordinate node management list 2b in the disk 2.
The information including the exclusion list and the designated resource name is sequentially delivered to the nodes 3 (node A, node B) immediately below.

In the node 3 (nodes A and B) directly below the management node 1, when the information is received, the distribution discrimination relay means 3a.
Starts and determines whether the own node name is included in the exclusion list in the received information. If it is not included, the resource specified in the own node is applied, and if it is included, it is applied. Without executing the process (skipping), the node name directly under the own node is taken out from the node management list 4a immediately under the disk 4 and delivered to each node 5 immediately below. In the lower layer of the node 3 and the lower nodes (nodes D and E) of the lower layer, the layers are sequentially distributed by the same process.

Here, when an error occurs in the transmission from the node 5 (node C) to one lower node D (no response for a certain period of time), the non-delivery information of the node 5 is created.
The relay means 5b is activated, and non-delivery information including the partner node name (node D) and the self node name (node C) for which the transmission has failed is created and sent to the node 3 (node A) immediately above.

Upon receipt of this non-delivery information, the node 3 (node A) adds its own node name (node A) and transmits it to the node immediately above. If the node immediately above is not the management node, the self-node name is sequentially added to the non-delivery information and transmitted to a higher node. In this example, the non-delivery information receiving means 1 is transmitted from the node 3 to the management node 1, and the management node 1
When the non-delivery information is received at b, the non-delivery information including each node name is stored in the area 2d in the disk 2.

After that, when a resend designation is issued to the management node 1, the resend information distribution means 1c is activated, and each node name (node D, node) on the path included in the non-delivery information 2d in the disk 2 is activated. C, node A is added in this order), which node is to be sent next is determined, and retransmission information including non-delivery information is transmitted to that node 3 (node A). Node 3 (node A) that received this resend information
Causes the retransmission information determining / relaying means 3c to be activated, deletes its own node name (node A) in the retransmission information, and transmits it to the next node 5 (node C) included in the retransmission information.

When the node C receives the resend information, the resend information determination / relay means 5c determines the content, determines that the own node is the node in which the transmission error has occurred, and activates the delivery determination relay means 3a. To do. As a result, the suspended node 5 (node C) to node D
Resume delivery of routes to. At this time, the delivery discrimination relay means 5a transfers only to a single node (node D), and the nodes below it refer to the node management list directly under the disk provided for each node.

[0021]

FIG. 2 is a hardware configuration diagram of an embodiment including a process of a management node, and FIG. 3 is a hardware configuration diagram of an embodiment including a process of a general node.

In FIG. 2, 1 is a management node, 10 is a main memory, 11 is a central processing unit, 12 is a channel for an auxiliary storage device for transferring information to and from the disk device 2, and 13 is a plurality of nodes connected to lower nodes. Is a communication control device to which the communication line is connected, 14 is an operating terminal provided with a display and a keyboard provided in the management node, and 2 is a disk device storing files.

Each control program is stored in the main memory 10, and 100 is a communication input / output program for controlling communication with a lower node connected via the communication control device 13,
101 is an operating system (OS), 102,
Reference numeral 103 is a file transfer control (reception) and (transmission) program, 104 is a non-delivery communication process activated by the file transfer control (reception) program 102, 105 is a redelivery process, 106 is a delivery process, and 107 is an operating terminal. Driven by an instruction from 14, the distribution process 10
6, a delivery operation process for activating 6, an operation terminal 14
It is a re-delivery operation process that is driven by an instruction from to start the re-delivery process. Each program or process represented by 100 to 108 included in the main memory 10 is executed by being processed by the central processing unit 11.

In the disk device 2, 20 is a program file in which a program relating to the present invention is stored,
Reference numeral 21 denotes each node name related to the non-delivery contained in the non-delivery information received from the lower node (the delivery destination node name which has not been delivered, the distribution source node name, each node of the route where the non-delivery information has been sent). Non-delivery information file storing name), 22 is an exclusion node list storing node names to which distribution information is not applied, 23 is a direct node list, and 24 is a case where information including a distributed resource is non-delivery. This is a non-delivery list in which related information such as the resource name and distribution time is stored for each non-delivery information. It should be noted that the disk device 2 also stores information about resources other than this, but the illustration thereof is omitted.

In FIG. 3, reference numeral 3 denotes a node, and each unit of 30 to 33 is a device similar to 10 to 13 in the management node of FIG. 2, 30 is a main memory, 31 is a central processing unit, and 32 is an auxiliary device. A storage device channel, 33 is a communication control device, and 4 is a disk device. In addition, 3 in the main memory 30
00 to 303 are respectively 10 in the management node of FIG.
0 to 103, 300 is an input / output program for communication, 301 is an operating system (OS), 30
Reference numerals 2 and 303 denote programs for file transfer control (reception) and (transmission).

Reference numeral 304 denotes a distribution process for distributing the distribution information received from the upper layer to the lower node, and 305 creates and transmits the non-delivery information when the distribution information does not arrive, or the non-delivery sent from the lower node. A non-delivery communication process that controls transmission of information to the upper node, an execution process 306 that executes distribution information in its own node, and a re-delivery process that controls re-delivery of re-delivery information to a lower node 307. Each program or process represented by 300 to 307 in the main memory 30 is executed by being processed by the central processing unit 31.

In the disk device 4, 40 is a program file in which a program relating to the present invention is stored, 4
1 is a non-delivery information file similar to 21 of the management node (the non-delivery information for storing the non-delivery information to be created in the own node and transmitting it to the upper layer is stored), 42 is a node whose own node or other nodes are excluded There is a list of excluded nodes (this list temporarily exists and moves to a higher or lower level), 43 is a direct node list. Note that 41 and 42 do not need to be provided in the lower nodes (management of each information becomes complicated).

FIG. 4 shows an example of the data structure of each file or list. FIG. 4 shows the data structure of each file or list stored in the disk device 2 or disk device 4 provided in each node shown in FIG. 2 and FIG. Is a non-delivery information file (21 in FIG. 2, 4 in FIG. 3)
1), the distribution destination node name (N1) at the time of transmission failure (transmission error etc.), the distribution source node name (N2) at the time of failure, and the node immediately above it. The name (N3), the node name (N4) two levels above, and the node name (Nn) immediately below the management node are sequentially stored.

The node name (N
n) is included in the non-delivery information supplied to the management node 1 (FIG. 2), but is a lower node that created the non-delivery information or a lower node 3 (FIG. 3) that relays the non-delivery information. It is not included in non-delivery information that occurs or is relayed.

B. of FIG. Is a data structure of the non-delivery list, and information about resources that have not been delivered due to a transmission error or the like is stored for each resource. A deletion flag is provided at the head of this list, and if the flag is "1", it indicates that the corresponding resource is undelivered, and if it is "0", the undelivered information on that line is deleted. It means that. After the flag, the undelivered resource name, the distribution time, and the file name in which the undelivered information is stored are sequentially stored.

C. of FIG. Is the data of the excluded node list, which consists of each node name that excludes execution. In addition, in FIG. Is the data of the node list immediately below, and is stored in each node (management node and lower nodes) and stores the name of the node connected directly below itself.

The contents of each process stored in the main memory of the management node shown in FIG. 2 and the lower node shown in FIG. 3 and executed by the central processing unit are shown in FIGS. FIG. 5 is a processing flow of the distribution process shown as 106 in FIG. 2 and 304 in FIG. When the distribution process starts, it determines whether its own node is the lowest node (leaf) (see FIG. 5).
S1), the process ends if it is the lowest, but if not, one record is read out from the immediate node list (23 in FIG. 2, 43 in FIG. 3) (S2 in FIG. 5), and the record ends (there is no record to read). If it is the end, the file data including the resource and the exclusion list is distributed to the node having the node name included in the record (S3 in FIG. 5). ).

Then, it is judged whether the distribution is normally completed (at step S5). If the distribution is completed, the process returns to step S2,
The next one record in the direct node list is read, and the distribution is repeated to other direct nodes by the same process. If the process does not end normally in step S5, a non-delivery information file (21 in FIG. 2, 41 in FIG. 3) including the destination node name, own node name, etc. is created (S6 in FIG. 5), and the own node is the management node. If it is not a management node, the non-delivery information is transferred to the node immediately above (S8), and if it is a management node, it is added to the non-delivery list (24 in FIG. 2) (S).
9).

FIG. 6 shows each processing flow of the non-delivery communication process and the execution process. A. of FIG. In the processing flow of the non-delivery communication process (104 in FIG. 2, 305 in FIG. 3) shown in FIG. 3, when this process starts by receiving non-delivery information, it is determined whether or not the node is the management node (S1 in A. of FIG. 6). , If it is a management node, then the B. Non-delivery list shown in (2 in FIG. 2)
Information such as resources that have not been delivered to 4) is added (S2 in A. of FIG. 6).

At this time, the non-delivery communication process of the management node does not perform the process of storing the non-delivery information in the non-delivery information file (21 in FIG. 2). If it is determined in step S1 that the node is not the management node, the non-delivery information file (4 in FIG.
The node name of its own is added to 1) (S3 in FIG. 6A), and it is transferred to the node immediately above (S4). This step S3
The process of S4 is sequentially performed by each lower node, so that the node names on the route are sequentially added.

Next, referring to FIG. The execution process shown in Fig.
306) is started when the resource (the file that can include the exclusion list) distributed from the upper node is received by the lower node, and the exclusion list file (which is received together with the resource or previously shown in FIG. Of the excluded node list 42 is transferred (S1 in B. of FIG. 6), and if not, the resource is executed (S4) and the process ends. If there is an exclusion list file, it is determined by checking whether or not its own node name is included (S2, S3). If it is found from this determination that the resource is included, the process ends without executing the resource, and if not included, the resource is executed (S4).

FIG. 7 is a processing flow of the redelivery process (105 in FIG. 2, 307 in FIG. 3). The redelivery process is
The management node is activated by the redelivery operation process (108 in FIG. 2), and the lower node is activated by the reception of redelivery information (additional non-delivery information) in the file transfer control program (reception) 302 (FIG. 3). . When started, received non-delivery information file (21 in FIG. 2, 41 in FIG. 3)
, It is determined whether there is one record (one node name) (S1 in FIG. 7). In this determination, the record included in the non-delivery information is deleted one by one as it approaches the node in which the error occurred, and one record (destination node name) is reached when the node in which the error occurs is reached. Done.

If the record is not one record (a node higher than the error occurrence node), the top record of the non-delivery information file is deleted (S2 in FIG. 7), and the redelivery file is sent to the lower node of the deleted record. Then (S3)
finish. If the non-delivery information file is one record in step S1, the non-delivery information file is distributed to the node indicated by the record (S4), and the non-delivery information file (2 in FIG. 2).
1, 41) in FIG. 3 is deleted (at step S5).

Then, it is judged whether the information transmitted by the re-delivery is normally transmitted and ended normally (S6). If the information is normally ended, the processing is ended. If not, the non-delivery information file (new No.) is created (at step S7), it is determined whether or not the node is a management node (at step S8), and if it is a management node, it is added to the non-delivery list (24 in FIG. 2) (S10 in FIG. 7). In the case, it is transferred to the node directly above (S9 of the same).

Next, FIG. 8 is a processing flow of the operation process. Is a delivery operation process, B. Is each processing flow of the redelivery operation process. A. The delivery operation process of
The distribution process (3 in FIG. 3) starts when the operator instructs distribution from the operation terminal (14 in FIG. 2) of the management node.
04) is started and it ends. B. The re-delivery operation process is also started by the operator of the operation terminal instructing re-delivery of delivery information that was not delivered due to a transmission error or the like after the error is recovered. When started, the non-delivery list (24 in FIG. 2) is displayed as a list (S1 in B. in FIG. 8). The operator is made to select one from the undelivered list displayed (S2), and it is determined whether the selection has been executed (S3). If not selected, the process ends, but if selected, redelivery is performed. The process (105 in FIG. 2) is started (at step S4), and the non-delivery list (at 24 in FIG. 2) and the non-delivery information file (at 21 in FIG. 2) are deleted (at step S5).

Next, a concrete operation example according to the present invention is shown in FIG. In the tree structure network shown in FIG. 9, nodes A and B are arranged directly under the management node, and nodes are arranged under the node A, but they are not shown.
Below the node B, as shown in the figure, node C, node D
Are arranged, and nodes E and F are further arranged below the node D.

In this state, the management node issues an instruction from the operation terminal to start the distribution operation process, add a node name (denoted as node D) as exclusion information, and specify resource information (denoted as x). When the distribution operation process is driven, the distribution process is activated and distribution is executed. That is, the resource x is transmitted to each node other than the node D (see FIG. 9).
of). In this case, the management node refers to the node list immediately below (23 in FIG. 2) and distributes to node A and node B, respectively, and the execution process (B. in FIG. 6) at node A.
Causes the resource x to be applied (executed) (in FIG. 9), and similarly the resource x is applied to the node C as well.

When the nodes A and B are also distributed to the nodes directly below them, and the information of the same content is distributed to the nodes C and D which are nodes directly below the node B (in FIG. 9), the node C The resource x is applied, but since the node D is added as exclusion information in the node D, the resource x is not applied by the processing of the execution process (B. in FIG. 6) (in FIG. 9).

The node D transmits the received information to the lower nodes E and F, but the transmission to the node E was performed well, but the delivery to the node F failed due to the occurrence of a transmission error. In the case (FIG. 9), the node D creates a file (A in FIG. 4) of the non-delivery information (in FIG. 9). To this non-delivery information, node F is added as the node name of the transmission partner, and node D is added as the node name of the transmission source. This non-delivery information is transmitted from the node D to the node B, which is the node immediately above (FIG. 9). Node B receiving this
A. of FIG. The non-delivery communication process shown in FIG. 9 adds the own node name (node B) to the non-delivery information (FIG. 9),
It is transmitted to the management node which is the node immediately above (in FIG. 9).
When the management node receives this non-delivery information (node names F, D, and B are added), the non-delivery list (B. in FIG. 4).
Add to.

In the management node, the occurrence of an error can be known by displaying a list of non-delivery information (non-delivery list) ((10) in FIG. 9).
The operator examines the relevant node, and eliminates the failure that is the cause of the error by instructing the person in charge of the relevant node ((11) in FIG. 9). When the failure is recovered, the re-delivery operation process (B. in FIG. 8) is activated by the operation terminal to deliver the same information to the node that could not be delivered due to the error last time.

Here, the non-delivery list is displayed in a list, and the non-delivery information (non-delivery information file) is selected ((12) in FIG. 9) and the redelivery process (FIG. 7) is started. Then, the selected non-delivery information file and non-delivery list are deleted.

The re-delivery process (FIG. 7) started determines whether there is one record (number of node names) in the non-delivery information file (A. in FIG. 4), and there are a plurality of records. (In the case of A. in FIG. 4, the node name directly below the management node at the bottom) is deleted, and the non-delivery information (node name B is deleted and node name D is deleted for node B of the deleted record). (Including F) is added and the resource information is redistributed ((13) in FIG. 9). Upon receiving the redelivery information, the node B, upon detecting that it is the redelivery information, starts the redelivery process (FIG. 7) and deletes the first record (including the node D as the node name) in the redelivery process. Then, the redelivery information is transmitted to the node D together with the non-delivery information (including the node name F).

Upon receipt of this, the node D activates the redelivery process of FIG. 7 and detects that the node name is one record (node F is stored as the node name). Accordingly, the node D distributes the distribution information to the node F ((14) in FIG. 9 and deletes the non-delivery information file created by itself when an error occurs. The node F receives the re-distributed resource information. Then, distribution is performed to the node immediately below the own node ((15) in FIG. 9).

[0049]

According to the present invention, it is possible to perform broadcast communication without being aware of the overall structure of the tree structure network, and at this time, it is possible to specify nodes that should be excluded from application.

Further, by automatically notifying the management node of the retransmission route to the node (including lower nodes) that could not be transmitted due to an error, an error occurred without newly designating a route at the time of re-delivery. Redelivery can be performed only for the nodes that could not be sent.

As a result, the communication cost can be greatly reduced. In addition, since the network structure is not taken into consideration, it is possible to quickly respond to system changes that occur during operation and improve the system operation rate.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a hardware configuration diagram of an embodiment including a process of a management node.

FIG. 3 is a hardware configuration diagram of an embodiment including a process of a general node.

FIG. 4 is a diagram showing a data configuration example of each file or list.

FIG. 5 is a processing flow of a distribution process.

FIG. 6 is each processing flow of a non-delivery communication process and an execution process.

FIG. 7 is a processing flow of a redelivery process.

FIG. 8 is a processing flow of an operation process.

FIG. 9 is a diagram showing a specific operation example according to the present invention.

FIG. 10 is an explanatory diagram of a conventional example.

[Explanation of Codes] 1 management node (route) 1a resource distribution means 1b non-delivery information reception means 1c retransmission information distribution means 2 management node disk 2a resources 2b direct node management list 2c exclusion list 2d non-delivery information 3 management node 1 Lower node (node A, node B) 3a Delivery determination relay means 3b Non-delivery information creation / relay means 3c Retransmission information determination / relay means 4 Disk of node 3 4a Direct node management list 5 Lower node of node 3 (node C , Node D) 5a delivery discrimination relay means 5b non-delivery information creation / relay means 5c retransmission information discrimination / relay means 6 disk of node 5 6a node management list directly under

Claims (3)

[Claims] 1. In a tree-structured network control method in which lower nodes are sequentially arranged in a tree shape with a management node as a vertex, and each node manages only the node directly under itself, the management node excludes resources and applications. A resource distribution means for broadcasting information including a list of nodes,
When the subordinate node receives the delivered information, it determines whether or not its own node corresponds to the exclusion list, and if not, applies the delivered resource to the own node and delivers the received information to the node immediately below the own node. A control method for a tree-structured network, which is provided with a delivery discriminating / relaying means. 2. The low-order node according to claim 1, when an error is detected in distribution to a node lower than the self-node, an error message containing information on the related node such as the partner node name and the self-node name in error. The non-delivery information creating / relaying means for creating the non-delivery information including the reachability information and sending it to the immediately above node is provided, and the nodes other than the management node receiving the non-delivery information are received by the non-delivery information creating / relaying means. A control method for a tree structure network, comprising: non-delivery information receiving means for adding the self-node name to non-delivery information, transmitting the non-delivery information to an upper node, and storing the non-delivery information when the management node receives the non-delivery information. 3. The management node according to claim 2, wherein the management node is
It is provided with a retransmission information distribution unit that is activated by a retransmission designation and re-distributes it to the lower node based on the stored non-delivery information, and the lower node receiving the retransmission information has its own node as an error detection node. If the node is not an error detection node, the own node added to the retransmission information is deleted, and the retransmission information determination / relay means for relaying the retransmission information to the next lower node included in the retransmission information is provided, When the own node is an error detection node, the resend information discriminating / relaying means activates the delivery discriminating / relaying means and restarts the delivery to the partner node in which the error is detected. method.