JP2743879B2 - Local area network controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a local area network control device for controlling input / output between a local area network and each terminal device connected to the local area network, and particularly to a new terminal device to be newly connected. The present invention relates to a local area network control device for detecting an overlap between an identification number on a network and an identification number of another terminal device already connected.

[0002]

2. Description of the Related Art In order to identify a source terminal and a destination terminal of data to be transmitted, in a local area network, an identifier (hereinafter, referred to as a unique identifier) of each connected terminal device.
Expressed as node ID. ). If terminal devices having the same node ID exist on the local area network, it is not possible to uniquely identify a data transmission destination and a data transmission source, and thus information cannot be transmitted properly. Normally, whether a node ID is duplicated is visually checked by a human.

[0003] Japanese Patent Application Laid-Open No. 3-267845 discloses a local area network control device for detecting duplication of IDs of nodes connected to a network. In this device, a local area network control device that performs an interface between each terminal and a network transmits a packet by designating its own node ID as a transmission destination. If there is no terminal device having the same node ID as the own device, the transmitted packet returns around the loop-shaped local area network. When a terminal device having the same node ID exists, the packet is received by the terminal device, and therefore, the terminal device does not return to its own device.

[0004] However, it is also assumed that a packet does not return due to a network failure or the like. Therefore, a special node ID that is not normally assigned to the terminal device is designated as a transmission source (own device) and a transmission destination (own device), and a packet is transmitted. When the packet whose own node ID is specified as the transmission destination does not return and the packet whose special node ID is specified as the transmission destination returns, the terminal device having the same node ID as that of the own device is transmitted to the network. Detecting that it is on top.

Also, a line information monitoring device, which is a dedicated terminal device for managing a network, is provided to centrally manage the connection status of each terminal device and the operation state of the entire network. The line information monitoring device is designed to centrally manage the entire network by exchanging management information with each terminal device through a local area network.

[0006]

When the node ID is confirmed by the eyes of a human, there is a problem that the confirmation may be artificially omitted and the operation of confirming the duplication is complicated. In the prior art disclosed in JP-A-3-123231, such a problem can be solved because each local area network control device automatically detects the duplication of the node ID. However, the node ID duplication is only individually recognized and displayed by each terminal device, and therefore the line information monitoring device cannot centrally manage the node ID duplication. For this reason, there is a problem that the network monitor must visit each terminal device and check for the presence or absence of duplication.

An object of the present invention is to provide a local area network control device capable of notifying another terminal device of alarm information indicating that node ID duplication has been detected.

[0008]

According to the first aspect of the present invention, a terminal identifier, which is a terminal identifier assigned to the terminal itself, among terminal identifiers for identifying terminal devices connected to a network is used. Self-terminal identifier storage means for storing; permanent-missing-number terminal identifier storing means for storing a permanent-missing-number terminal identifier predetermined as a terminal identifier that is not assigned to each terminal device connected to the network; First network subscribing means for subscribing to the network by using the own terminal identifier stored in the first network subscribing means, and own terminal identifier stored in the self terminal identifier storing means when subscribing to the network by the first network subscribing means. Checks whether another terminal device assigned the same terminal identifier exists on the network. And the overlapping terminal identifier detection means for,
A network subscription suspending unit for suspending the first network joining unit from joining the network when the duplicate terminal identifier detecting unit detects the presence of a terminal device to which the same terminal identifier as the own terminal identifier is assigned; A second network subscriber for subscribing to the network using the permanent missing terminal identifier after the subscribe to the network is terminated by the network subscriber, and a self-terminal identifier after subscribing to the network by the second network subscriber. The local area network control device includes terminal identifier duplication notifying means for notifying another terminal device via a network that there is a terminal device to which the same terminal identifier is assigned.

That is, according to the first aspect of the present invention, when the presence of a terminal device having the same terminal identifier as that of the own terminal is detected when joining the network, the joining of the network by the own terminal identifier is stopped. I do. Then, the terminal joins the network using a permanent missing terminal identifier that is not assigned as a terminal identifier, and notifies other terminal devices via the network that the own terminal identifier is duplicated. Even if the own terminal identifier is duplicated, it is possible to join the network using the permanent missing terminal identifier, so that the duplication of the own terminal identifier can be notified through the network.

[0010] According to the second aspect of the present invention, an own terminal identifier storage for storing an own terminal identifier which is a terminal identifier assigned to the own device among terminal identifiers for identifying each terminal device connected to the network. Means, a permanent missing terminal identifier storing means for storing a predetermined permanent missing terminal identifier as a terminal identifier which is not assigned to each terminal device connected to the network, and a self-service identifier stored in the own terminal identifier storing means. First network joining means for joining a network using a terminal identifier, and assignment of the same terminal identifier as the own terminal identifier stored in the own terminal identifier storing means when joining the network by the first network joining means Duplicate terminal identification to detect whether another terminal device When the child detecting means and the duplicate terminal identifier detecting means detect the existence of a terminal device to which the same terminal identifier as the own terminal identifier is assigned, the first network joining means stops the joining to the network. Network joining suspending means, second network joining means for joining the network using the permanent missing terminal identifier after suspending the network joining by the network joining suspending means, and the second network joining means.
Terminal identifier duplication notifying means for notifying another terminal apparatus through the network that there is a terminal device assigned the same terminal identifier as the terminal identifier after joining the network by the network joining means, and this terminal identifier duplication notifying means The local area network controller is provided with network departure means for deviating itself from the network when notification of duplication of the terminal identifier to other terminal devices is completed.

According to the second aspect of the present invention, when the presence of a terminal device having the same terminal identifier as that of the own terminal is detected when joining the network, the joining of the network by the own terminal identifier is stopped. I do. Thereafter, any terminal device joins the network using a permanent missing terminal identifier that is not used as its own terminal identifier, and reports the duplication of its own terminal identifier via the network. Further, after the notification, the terminal has left the subscribed network by the permanent missing terminal identifier. Even if the own terminal identifier is duplicated, it is possible to join the network using the permanent missing terminal identifier, so that the duplication of the own terminal identifier can be notified through the network. Further, by leaving the network after the notification, continuous use of the permanent missing terminal identifier is avoided.

In the invention according to claim 3, the terminal identifier duplication notifying means notifies other terminal devices that there is a terminal device to which the same terminal identifier as the own terminal identifier is allocated and the terminal identifier. ing.

In other words, according to the third aspect of the present invention, the duplication of the own terminal identifier and the duplicated terminal identifier are notified to other terminal devices through the network. As a result, the terminal device that has received the notification can determine which terminal identifier assigned to which terminal has been duplicated.

[0013] In the invention according to claim 4, the terminal identifier duplication notifying means notifies a network management terminal device that manages the network that there is a terminal device to which the same terminal identifier as the own terminal identifier is assigned. doing.

In other words, according to the fourth aspect of the present invention, the terminal device for network management is notified that the terminal identifier is duplicated, so that the terminal identifier duplication can be centrally managed.

[0015]

FIG. 1 shows an outline of a configuration of a local area network control device according to an embodiment of the present invention. The local area network control device 11 (hereinafter, referred to as a control LAN device) is connected to a communication cable 12 of the local area network. An external device 13 is connected to the control LAN device 11 as a terminal device. The control LAN device 11
A circuit device for inputting and outputting various data to and from a local area network according to a predetermined protocol. The external device 13 exchanges various data with the network via the control LAN device 11. Various external devices (not shown) are connected to the network communication cable 12 via control LAN devices. External devices include a host computer, a printer, and a server. As one of the external devices, a network management host computer for centrally managing the entire local area network is connected. The host computer for network management is called a line information monitoring device.

The control LAN device 11 includes a CPU (central processing unit) 21 which performs a central function of various controls. The CPU 21 includes a ROM (Read Only Memory) for storing programs and fixed data and a random access memory for temporarily storing data required for executing the programs. I have. Various circuit devices are connected to the CPU 21 via various buses 22 such as a data bus and a control bus. Among them, the ID storage memory 23 is a nonvolatile random access memory. The ID storage memory 23 stores a node ID as an access number for identifying each terminal device on the network. ID storage memory 23
The node ID storage area 24 is an area for storing the own node ID which is the node ID assigned to the own terminal. The permanent missing node ID storage area 25 is an area for storing a permanent missing node ID predetermined as a node ID that is not assigned to any terminal device connected on the network.

The LAN transmission / reception unit 26 is a communication device for performing protocol control with a network, and is connected to the communication cable 12. The parallel input / output unit 27 is an interface circuit for inputting / outputting various data to / from the external device 13 in a parallel format. The serial input / output unit 28 transmits various data to the external device 1 in serial form.
3 is an interface circuit for inputting / outputting data to / from the device.

FIG. 2 shows a flow of processing performed when the control LAN device shown in FIG. 1 newly joins the network. In the node ID storage area 24 of the control LAN device 11, the own node ID used when joining the network is registered in advance. The node ID is
It can take any value from "0" to "FF" (hexadecimal notation), and the permanent missing node ID is set to "FF". Each terminal assigns a number other than “FF” to its own node I
Used as D. Here, the own node ID which is the node ID of the own terminal is stored by two rotary type dip switches. Further, the permanent missing node ID “FF” is also set by two rotary dip switches.

When newly joining the network, the control LAN device 12 sends and receives a series of commands specified by the protocol and performs a process of joining the network (step S101). At this time, an attempt is made to join the network using the own node ID number stored in the node ID storage area 24. The control LAN device 12 receives from the network a response message indicating whether a terminal device having the same node ID as the node ID used at the time of joining is already connected to the network. Based on this response message, the CPU 21 determines whether a terminal device having the same node ID already exists in the network and its own node ID is duplicated (step S102).

If there is no overlap (step S1)
02; N), the own node ID set in the node ID storage area 24 is set as the node ID of the determined own terminal (step S103.)
Completes the participation in the network (step S1)
04). When it is detected that the node IDs are duplicated (step S102; Y), the access to the network by the number stored in the node ID storage area 24 is stopped, and the permanent missing node ID is set to the own device. Node ID
(Step S105). Then, it joins the network using the permanent missing node ID (step S106).

After terminating the network with the permanently missing node ID, an alarm notification indicating that the own node ID stored in the node ID storage area 24 is duplicated is sent to the line information monitoring device through the network. It is sent (step S107). After the end of the notification processing, the CPU 21 disconnects the control LAN device from the network (step S108). The line information monitoring device is notified that the duplicate node ID has been detected, and which number the duplicate node ID is. The line information monitoring device displays the notified contents on a display, emits a predetermined alarm sound, and
Warn the administrator of the duplication of D.

FIG. 3 schematically shows a change in the network connection status when joining with a duplicate node ID. In the state before joining (a in the figure), the network 31 has the first node 32 with the node ID “01”, the second node 33 with the node ID “02”, and the node ID “03”. Third set to "
Is connected to the node 34. In a state where the fourth node 35 is trying to join with the node ID “02” (b in the same figure), the node IDs of the second node 33 and the fourth node 35 are both “02” and are duplicated. The fourth node is denied access to the network. In this state, the fourth node 35 can recognize that the node ID “02” is duplicated, but cannot notify other nodes because it cannot join the network.

Therefore, the control LAN device re-joins the network by using the previously reserved permanent missing node ID “FF” (FIG. 3C). And node I
An alarm notification 36 indicating that D “02” is duplicated is sent to the first node 32 via the network 31. Thereafter, the fourth node leaves the network (d in the figure).

[0024]

As described above, according to the first aspect of the present invention, when the own terminal identifier is duplicated, the terminal joins the network using the permanent missing terminal identifier. Duplication can be notified to another terminal device. For example, if a notification is sent to a management terminal device that integrally manages the network, duplication of terminal identifiers can be easily and centrally managed without an administrator going to each terminal device.

According to the second aspect of the present invention, when the own terminal identifier is duplicated, the terminal is joined to the network with the permanent missing terminal identifier. Can be notified. Further, after the notification, the terminal is disconnected from the network subscribed to by the permanent missing terminal identifier, so that the continuous use of the permanent missing terminal identifier can be avoided.

According to the third aspect of the present invention, in addition to the fact that the own terminal identifier is duplicated, the duplicated own terminal identifier is notified to other terminal devices via the network. As a result, the terminal device that has received the notification can recognize which terminal identifier assigned to which terminal is duplicated.

According to the fourth aspect of the present invention, the terminal device for network management is notified that the terminal identifier is duplicated, so that the terminal identifier duplication can be easily and centrally managed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an outline of a configuration of a local area network control device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a flow of processing performed when the control LAN device shown in FIG. 1 newly joins a network.

FIG. 3 is an explanatory diagram schematically showing a change in a network connection state when joining with a duplicate node ID.

[Explanation of symbols]

 11 Control LAN Device 12 Network Communication Cable 13 External Equipment 21 CPU 22 Bus 23 ID Storage Memory 24 Node ID Storage Area 25 Permanently Missing Node ID Storage Area 26 LAN Transmitter / Receiver

Claims (4)

(57) [Claims] 1. An own terminal identifier storing means for storing an own terminal identifier which is a terminal identifier assigned to the own device among terminal identifiers for identifying respective terminal devices connected to a network; A permanent missing terminal identifier storage unit that stores a predetermined permanent missing terminal identifier as a terminal identifier that is not assigned to each connected terminal device, and a own terminal identifier stored in the own terminal identifier storing unit. Means for subscribing to the network, and when the first network subscribing means subscribes to the network, the same terminal identifier as the own terminal identifier stored in the own terminal identifier storage means is allocated. Duplicate terminal identification to detect if there is another terminal device on the network Child detecting means; and when the duplicate terminal identifier detecting means detects the presence of a terminal device to which the same terminal identifier as the own terminal identifier is assigned, joining the network by the first network joining means. Network subscription suspending means for suspending access to the network by means of the network subscription suspending means, and then subscribing to the network by using the permanent missing terminal identifier; and second network joining means. Terminal identifier duplication notifying means for notifying another terminal device through the network that there is a terminal device assigned the same terminal identifier as the own terminal identifier after joining the network. Local area network controller. 2. An own terminal identifier storing means for storing an own terminal identifier which is a terminal identifier assigned to the own device among terminal identifiers for identifying respective terminal devices connected to a network; A permanent missing terminal identifier storage unit that stores a predetermined permanent missing terminal identifier as a terminal identifier that is not assigned to each connected terminal device, and a local terminal identifier stored in the local terminal identifier storing unit. Means for subscribing to the network, and when the first network subscribing means subscribes to the network, the same terminal identifier as the own terminal identifier stored in the own terminal identifier storage means is allocated. Duplicate terminal identification to detect if there is another terminal device on the network Child detecting means, and when the duplicate terminal identifier detecting means detects the presence of a terminal device to which the same terminal identifier as the own terminal identifier is assigned, joining the network by the first network joining means. Network subscription suspending means for suspending access to the network by means of the network subscription suspending means, and then subscribing to the network by using the permanent missing terminal identifier; and second network joining means. Terminal identifier duplication notifying means for notifying another terminal device through the network that there is a terminal device assigned the same terminal identifier as the own terminal identifier after joining the network, Duplicate terminal identifier for other terminal devices A local area network control device comprising: a network departure unit that departs itself from the network when the notification is completed. 3. The terminal identifier duplication notifying means notifies another terminal device of the existence of a terminal device to which the same terminal identifier as the own terminal identifier is assigned and the terminal identifier. Claim 1 or Claim 2
A local area network control device as described. 4. The terminal identifier duplication notifying means notifies a network management terminal device that manages the network that there is a terminal device to which the same terminal identifier as the own terminal identifier is assigned. 3. The local area network control device according to claim 1, wherein: