JPH09223092A - Method and system for managing network - Google Patents

Abstract

PROBLEM TO BE SOLVED: Not only to eliminate necessity for the manager of a network to be skilled in work for judging the operating conditions of the network by relating and integrating respective kinds of information but also to prevent measures from being delayed by missing a generated problem or wrong measures from being taken. SOLUTION: Concerning this method, in order to manage the network, the information is held as one object for every piece of connected equipment (S1), and a state symbol to be generated based on the information of the object is generated, displayed on a network constitution diagram and presented for the network manager (S2). When an abnormality is generated at the connected equipment, the information of the object is updated based on received fault information (S3), the updated state symbol is generated and displayed on the network constitution diagram (S4) and based on the displayed information, the fault recovery is operated to the connected equipment (S5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network management method and system, and more particularly, to efficiently share equipment in a network and quickly deal with occurrence of abnormality in the network to maintain communication quality. The present invention relates to a network management method and system for operating and managing a network system for achieving the above.

[0002]

2. Description of the Related Art A conventional network system management method graphically displays a physical connection configuration of equipment as a network configuration diagram by collecting and managing information about servers and clients connected to the network. There is a way to do it.

In addition, device information relating to the functions and performance specifications of each device, performance information relating to the load condition and operating rate of each device, and traffic information relating to the communication condition within the network are individually provided. As a general method, a person who displays them separately and manages the network associates these pieces of information with each other and comprehensively judges the operation status of the network.

Further, when it becomes necessary to change the network configuration or performance due to equipment failure or concentration of communication to a specific device, dedicated software is used for each device to control it. Information is input / instructed individually.

[0005]

In the conventional network system management method, whether or not a problem has occurred in the operating network and whether or not it is necessary to take measures against the problem that has occurred are individually determined. It is up to the human judgment to associate and integrate the information. Therefore, it is not only necessary for the person who manages the network to be familiar with the task of associating and integrating individual pieces of information to determine the operational status of the network. There are problems such as taking measures.

Further, in order to change the configuration and performance of the network, it is not only necessary to learn the control information unique to each device, but there is also the problem that incorrect information is input / instructed. In addition, there is also a problem that it is difficult to promptly deal with a problem that has occurred because the input operation takes time.

The present invention has been made in view of the above points, and a person who solves the above-mentioned conventional problems and manages a network determines the operational status of the network by associating and integrating individual information. It is an object of the present invention to provide a network management method and system capable of managing a network without being familiar with the work for doing so.

A further object of the present invention is to provide a network management method and system in which it is not necessary to learn control information unique to each device and its input operation method in order to change the network configuration and performance. is there.

[0009]

SUMMARY OF THE INVENTION The present invention is a network management method for managing a network to which a plurality of network connection devices are connected. When a failure occurs in the network connection device, the network manager graphically displays the failure information. To prompt the user to understand the state of the network, and to remotely perform the failure recovery operation for the network-connected device in which the failure has occurred.

FIG. 1 is a diagram for explaining the principle of the present invention. In order to manage a network, the present invention holds MIB information, setting information, and a management method of a connected device as one object for each connected device (step 1), and a connection relationship between a server, a client, and a connected device that form a network. A state symbol generated based on the information of the object is generated and displayed on the network configuration diagram drawn based on (1) and presented to the network administrator (step 2), and when the failure information is received from the connected device,
The information of the object is updated based on the fault information (step 3), and the status of the connected device is generated and displayed on the network configuration diagram based on the updated object by generating a status symbol (step 4). Based on the information obtained, an instruction operation for failure recovery to the connected device is performed (step 5).

Further, according to the present invention, in step 4, when the status symbol is also displayed on the network configuration diagram, if failure information is received, an alarm display is also performed. In step 4, when an alarm is displayed, the display screen blinks yellow.

Further, according to the present invention, in step 5, when the failure occurred in the network is restored, the status symbol is operated to extract and display the MIB information and the setting information from the information of the object of the device. A message for changing the setting of the connected device on the display screen is created based on the information of the object, and the message is transmitted to the device.

Further, according to the present invention, a symbol imitating a traffic sign is displayed as a state symbol. FIG.
It is a principle block diagram of this invention. The network management system of the present invention includes a transmitting / receiving unit 100 that transmits / receives a message to / from a connection device connected to a network,
An object management unit 300 that converts information of various formats and contents that can be acquired from the connected device into a unified format and manages it as an object, and presents the operating status of the connected device as graphical information to the network administrator based on the object. The state display unit 200 and the instruction operation unit 400 that performs an instruction operation on the connected device according to the operating state of the connected device displayed by the state display unit to change the object and the graphical information.

The status display means 200 uses a configuration diagram display means 210 for displaying a connection relationship between connection devices constituting a network as a network configuration diagram and an object managed by the object management means 300. The symbol generation means 220 for generating a state symbol expressing the state of (1) and the symbol presentation means 230 for presenting the symbol generated by the symbol generation means 220 to the network manager.

When the failure information is input from the connection device, the above-mentioned instruction operation means 400 converts the failure information into graphical information and presents it to the network manager, and a failure information presenting means 410 and a symbol. Presenting means 23
The state symbol of the network device is grasped by the symbol presented by 0, the setting of the connected device is changed based on the object, and the state symbol display unit 420 changes the display of the state symbol and the state symbol change unit 420.
And a message generation unit 430 that generates a message for restoration processing for the connected device based on the display of the status symbol changed by the above and transfers it to the transmission / reception unit 100.

The fault information presenting means 410 described above is
An alarm means is provided for displaying an alarm when the failure information is presented to the network administrator. Further, the symbol presenting means 230 uses a symbol simulating a traffic sign as a state symbol.

Further, the above-mentioned object management means 300
Includes an information holding unit 310 that holds MIB information, performance information, setting information, or network service usage status information for each connected device. As described above, according to the present invention, in a network in which a plurality of routers, bridges, hubs, computers, and other network-connected devices are connected, when some failure occurs in the device, the failure information received from the device is graphically networked. The information is presented to the administrator to prompt the user to grasp the network status, and the failure recovery can be performed remotely from the network management system.

Further, the network management system of the present invention manages the status of each connected device, holds MIB information, setting information, etc. for each connected device as one object, and when the information is changed, , Change the object. Then, when the network management system receives the failure information transmitted from the connection device, the network manager displays an alarm by blinking yellow or the like on the display where the failure occurs in the network configuration. This allows the network administrator to easily gaze at the connection device in which the failure has occurred.

Further, according to the present invention, the network management system creates a state symbol representing the state of the connected device by using the information of the object to show the current state of the network, and the state symbol is displayed on the network configuration diagram. To display. In the past, information for managing various connected devices connected to a network was referred to MIB information, which is general management information, whereas objects for each connected device were referred to. By creating and managing it, it becomes possible to generate a state symbol with reference to detailed information.

When the network management system restores the failure of the connected device, the status information is manipulated to change the MIB information from the object of the connected device.
Performance information, and if the device is a computer, the usage status of the network service is extracted and displayed. By changing the displayed display information on the display screen, the network management system changes the settings for the connected device differently for each device, generates a message based on the object information, and a failure has occurred. Send to the connected device. In the past, this method was a management method using a management method unique to each connected device, but in the present invention, there is a change etc. by creating and managing an object for each connected device. Even if it does, consistent management can be achieved consistently.

As described above, according to the present invention, the information of various formats and contents obtained from the devices connected to the network is converted into a unified format and displayed as integrated information, so that the network administrator It is possible to grasp the operation status of the network without associating and integrating individual information.

Further, since the integrated information is an object that can be directly operated by a pointing device such as a mouse, the network configuration and the network configuration can be quickly and appropriately learned without learning the control information unique to each device and its input operation method. It is possible to change the performance.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows the configuration of a network management system of the present invention. The network management system includes a display unit 4, a status symbol creation unit 5, a network configuration diagram creation unit 6, a network device information processing unit 7, a network management control unit 8, a network connection device information storage unit 9, a message processing unit 12, and a message reception. It is composed of a unit 13 and a message transmitting unit 14. In addition, in relation to FIG. 2, the display unit 4 displays the symbol presenting means 230.
In addition, the status symbol creating unit 5
Is the symbol generation means 220, the network configuration diagram creation section 6 is the configuration diagram display means 210, the network management control section 8 is the instruction operation means 400, the network connection device information storage section 9 is the object management section 300, and the message is The processing unit 12 is the message generating unit 430, and the message receiving unit 13 and the message transmitting unit 14 are the transmitting / receiving unit 1.
00 respectively.

The network connection device information storage unit 9 includes identifiers of connection devices connected to the network, connection relationships between connection devices, clients, servers, bridges,
Connected device list 10 that holds information such as router type
And a connected device object 11 including MIB information, performance information, and setting information for each device, and holds setting information and operation information of network-connected devices.

The network configuration diagram creating unit 6 refers to the connected device list 10 in the network connected device information storage unit 9 and uses a plurality of devices, a server for providing a specific function to the devices, and a server. Creates and draws a configuration diagram of a network composed of clients.

The state symbol creating unit 5 refers to the connected device object 11 of the network connected device information storage unit 9 on the network configuration diagram created by the network configuration drawing creating unit 6 to indicate the operating state of the network connected device. Create a symbol that simulates a traffic sign
draw.

The network-connected device information processing unit 7 collects, processes, and displays the information of the devices connected to the network according to the input from the display unit 4. Specifically, the content of the connected device object 11 in the network connected device information storage unit 9 is changed. The network management controller 8
The instruction operation process of the network connection device information processing unit 7 is controlled.

The display unit 4 displays the network configuration diagram and the status symbols of the network-connected devices, and directs an instruction operation from the display. At this time, other devices connected to the network are directly operated via the network management control unit 8. The message processing unit 12 converts an instruction operation for the network connection device issued from the network management control unit 8 into an instruction operation for network management and creates a message instructing the network connection device.

The message receiving unit 13 receives a message from the network connection device. The message transmission unit 14 transmits the message generated by the message processing unit 12 to the network.

Next, the outline of the operation of each of the above components will be described with reference to FIGS. FIG. 4 is a flow chart for explaining the general operation of the network management system of the present invention. Step 101) When the network management system 1 is activated, the network management control unit 8 checks the current network status. Therefore, what kind of connected device is connected to the network and the connected device list in which the data of the connected device is registered. The current operation information is requested to each connected device based on the data of 10.

Step 102) The message processing unit 12 receives the request, converts the request into a message for requesting the connection device, and the message is sent to each network connection device via the message transmission unit 14. Step 103) The network-connected device that receives the message returns the operation information to the network management system as a message.

Step 104) The message receiving unit 13 of the network management system receives the message from the connection device and transfers it to the message processing unit 12. The message processing unit 12 receives the message, converts it into information that can be processed by the network management system 1, and delivers it to the network management control unit 8.

Step 105) The network management controller 8 updates the information of the connected device object 11 corresponding to each connected device inside the network connected device information storage 9 based on the received information. Step 106) Furthermore, the network management control unit 8
Controls to refer to the data of the connected device object 11 by the state symbol creation unit 5 and the network configuration diagram creation unit 6. As a result, the status symbol creation unit 5 creates an icon that is represented by a symbol simulating a traffic sign that allows the operating status of each network-connected device to be seen at a glance.

Step 107) The network configuration diagram creation unit 6 creates a network configuration diagram from the connection state of the network connection devices, and displays the operating state on the display unit 4 in the network configuration diagram and the position of the connection device on the configuration diagram. Display the icon. Step 108) The network administrator looks at the displayed icon indicating the operating status of the connected device and makes settings for failure recovery. The network management control unit 8 updates the connected device object having the contents of the network connected device information storage unit 9 by this setting.

Step 109) Based on the updated connected device object 11, the state symbol creating section 5
Regenerate and display the icon that is the status symbol. Step 110) The message processing unit 12 generates a message of an instruction operation for the connected device based on the generated icon and transfers the message to the message transmission unit 14.

Step 111) Message sending unit 14
Transmits the message to the connected device.
The message received by the message receiving unit 13 is
The information is used to notify the connected device of the occurrence of anomalies such as fault information and traffic congestion.

As the status symbol generated by the status symbol creating section 5, a symbol simulating a traffic sign is used. A feature of the present invention is that when such failure information is received, the operating status of the connected device is reflected in the connected device object 11, and a status symbol corresponding to the connected device is generated on the network configuration diagram and By displaying it, the system administrator is presented with the information, and the system administrator recognizes the current operating status of the connected device from the presented display screen and gives an instruction to the connected device. As a result, the instruction content is automatically reflected in the connected device object 11 that automatically manages the state information of the connected device, and the status of the connected device is centrally managed.

[0038]

Embodiments of the present invention will be described below with reference to the drawings. As an example shown below, a case where a failure in a congestion state occurs due to access to services provided by the server 1 from all clients connected to the server (server name 1) where the network administrator exists based on FIG. Will be described.

The figure is a network configuration diagram in which status symbols are also displayed. It is assumed that an identifier is uniquely assigned to all the connected devices shown in FIG. In the following example, the connected device to be used is "server name 1"
Server and client with "client name 1",
The client is “client 2”.

FIG. 6 shows an example of status symbols according to an embodiment of the present invention. This figure represents the state of the network by simulating traffic signs as symbols. FIG.
"Currently, the maximum packet transfer speed is 50 units or the communication speed is 30 unit speed. As the load increases,
The display changes to blinking yellow. Has the meaning.

The figure (B) has the meaning of "pointing to a setting such that the right line cannot be communicated by a router or a bridge". FIG. 3C shows “display of line disconnection or failure”. The same figure (D) indicates "setting of communication stop".

In FIG. 6E, "maintenance work is being performed".
It means that. The figure (F) indicates that the network use is set to be prioritized over other computers.
Part (G) of FIG. 6 indicates that “network use is restricted more than other computers”.

FIG. 6H shows that "the line is congested and communication cannot be performed easily." (I) of the figure shows that "the load of the line has exceeded the limit". FIG. 7 is a flowchart showing a specific operation of the network management system according to the embodiment of the present invention. 8 and 9 show display examples of the display unit of the network management system according to the embodiment of the present invention. In the following description, the server having the “server name 1” in FIG. 5 is initially “currently 45 units of packet transfer rate with respect to maximum 150 unit packet transfer rate”.

Step 201) The network management system 1 is waiting for an event. Here, since the server with the “server name 1” in FIG. 5 has become overloaded, the server with the “server name 1” sends a failure message to the network management system. At this time,
The message sent from the server with "server name 1" to the network management system indicates that "there is currently 140 unit speed with respect to the maximum 150 unit packet transfer speed, and traffic is in a traffic jam state".

Step 202) The network management system judges whether it is a user input or a message reception. If it is a user input, it moves to step 209, and if it is a message reception, it moves to step 203. Step 203) In this example, the network management system determines that the received message is the message reception, not the user input.
3 receives a message from the server "server 1".

Step 204) Message receiving unit 13
Transfers the received message to the message processing unit 12. The message processing unit 12 converts the received message into information that can be processed by the network management system 1. Step 205) The network management control unit 8 updates the connected device object 11 in the network connected device information storage unit 9 based on the received message. Initially, the connected device object 11 indicates “currently 45 for a maximum packet transfer rate of 150 units.
“Packet transfer rate per unit” is stored, and by this update, the contents of the connected device object 11 are “currently 14 for the maximum packet transfer rate of 150 units”.
It is updated to 0 unit speed. ”As a result, the network management control unit 8
Instructs the state symbol creating unit 5 to create a state symbol based on the updated contents of the connected device object 11.

Step 206) State symbol creating section 5
Refers to the connected device list 10 of the network connected device information storage unit 9 acquired via the network management control unit 8 and the connected device object 11 of “server name 1”, and as shown in FIG. An icon represented by a symbol simulating a traffic sign that allows the operating status of the server name 1 ") to be seen at a glance is created and transferred to the display unit 4.
When the state symbol creating section 5 creates the symbol,
The “server name 1” is previously set in the connected device object 11.
If a limit value (for example, 100) in the server is set and exceeds the limit value, the symbol is generated by adding the icon "congested" to the display.

Step 207) The network block diagram generator 6 acquires the connected device list 1 of the network connected device information storage 9 acquired via the network management controller 8.
0 to create a network configuration diagram and display unit 4
Transfer to Step 208) The display unit 4 redraws the network configuration diagram received from the network configuration diagram creation unit 6,
On top of that, the icon representing the state is displayed at the position of the connection device (server name 1) that is the transmission source of the message generated by the state symbol creation unit 5. Go to step 201.

A display example displayed on the display unit 4 at this time is shown in FIG. In the example in the figure, the connected device (server name 1)
At a maximum packet transfer rate of 150 units,
At present, the unit speed is 140 units, which indicates that the alarm display is blinking yellow.

Step 209) Next, the network administrator looks at the contents of FIG. 8 displayed on the display unit 4,
Recognize that disaster recovery measures must be taken. Therefore, as a countermeasure, in order to reduce the load on the server of "server name 1", the client of "client name 1",
The flow when the service of the server of "server name 1" used by the client of "client name 2" is to be stopped is shown below.

The network administrator clicks the status display icon of "client name 1" whose setting is to be changed. Step 210) The display unit 4 detects the click of the icon and notifies the network device information processing unit 7 of the connected device (“client name 1”) clicked.
The network processing unit 7 requests the network management control unit 8 for a selection list for displaying the information of the connected device.

Step 211) Based on the request, the network management control unit 8 extracts the required information selection list from the connection device object 11 in the network connection device information storage unit 9 and sends it to the network device information processing unit 7. respond. Step 212) The network device information processing section 7
An information list is created based on the information and displayed on the display unit 4.

Step 213) The network administrator clicks the item of "service" from the list of "client name 1" for stopping the use of the network service.This state is shown in FIG. In the example, for the client with "client name 1",
Stop the provided "image service." These operations are specified by the network administrator by clicking the mouse.

Step 214) The network device information processing section 7 requests the network management control section 8 for information on the clicked item. Step 215) The network management control unit 8 extracts necessary item information from the connection device object 11 and responds to the network device information processing unit 7.

Step 216) The network device information processing section 7 displays the information on the display section 4. Step 217) In order to stop the use of the network service, the network administrator clicks the “image service” item in the display of the currently used service list derived from the “service” item.

Thereafter, by repeating the same operation from step 213 to step 216 for the client of "client 2", the use of the service is added to the list derived from the item of "image service" as shown in FIG. Since the items of "restriction" and "stop" related to the setting appear, the network administrator selects and clicks "stop" in this example.

Step 218) Upon receiving the input, the network device information processing section 7 requests the network management control section 8 for the setting change content of the clicked item. Step 219) The network management control unit 8 issues a setting change request to the message processing unit 12 for the connected device for which the setting change is requested.

Step 220) Message processing unit 12
Converts the contents into a message to the connected device (“client name 1” “client name 2”). Step 221) A message for setting change is transmitted to the connected device (“client name 1” “client name 2”) via the message transmission unit 14.

The network management system 1 is now
Waiting for an event. Then, by receiving the message from the connected device whose setting has been changed, the network management system reflects the result of the setting change in the network device information storage unit 9 and displays the state on the display unit 4.

As described above, the network administrator refers to the status symbol on the network configuration diagram of the display unit 4 and repeats the direct remote control operation to enable proper network management. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified and applied within the scope of the claims.

[0061]

As described above, according to the present invention, on the display screen of the network management system, by displaying the state symbol simulating the traffic sign representing the performance information of the connected device on the network configuration diagram in a superimposed manner. As a result, the network administrator can easily grasp the current state of the network, and it is less likely to overlook the problems that have occurred.

Further, in order to take measures against a failure that has occurred on the network, the network administrator clicks a symbol displayed on the network configuration diagram of the network management system using a pointing device such as a mouse to connect the connected device. By selecting and inputting from the menu items displayed together with the symbol display, it becomes possible to easily limit the use of clients and change the network configuration. As a result, without having to be aware of the setting method and management tools for each network connection device,
It is possible to perform appropriate network management quickly and easily from a unified interface.

As described above, the network management system collects performance information and control information specific to each network-connected device and realizes network failure detection and subsequent measures against the failure on a unified interface. As a result, network management can be performed appropriately, easily, and promptly, so that the network administrator can work efficiently and the time required for troubleshooting can be shortened.

By applying the present invention to management in a network in which various computers and connected devices are connected, such as a computer network in a company, management is very easy and quick response in the event of a failure becomes possible. .

[Brief description of drawings]

FIG. 1 is a diagram for explaining the principle of the present invention.

FIG. 2 is a principle configuration diagram of the present invention.

FIG. 3 is a configuration diagram of a network management system of the present invention.

FIG. 4 is a flowchart for explaining a schematic operation of the network management system of the present invention.

FIG. 5 is a diagram showing a first screen display example of the network management system according to the embodiment of the present invention.

FIG. 6 is a diagram showing an example of status symbols according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a specific operation of the network management system according to the exemplary embodiment of the present invention.

FIG. 8 is a diagram showing a second screen display example of the network management system according to the embodiment of the present invention.

FIG. 9 is a diagram showing a third screen display example of the network management system according to the embodiment of the present invention.

[Explanation of Codes] 1 network management system 2 network administrator 3 network connection device 4 display unit 5 status symbol creation unit 6 network configuration drawing creation unit 7 network device information processing unit 8 network management control unit 9 network connection device information storage unit 10 Connected device list 11 Connected device object 12 Message processing unit 13 Message receiving unit 14 Message receiving unit 100 Transmitting / receiving unit 200 Status display unit 210 Configuration drawing display unit 220 Symbol generating unit 230 Symbol presenting unit 300 Object managing unit 310 Information holding unit 400 Instructing operation Means 410 Failure information presenting means 420 Situation symbol changing means 430 Message generating means

Claims (12)

[Claims] 1. A network management method for managing a network to which a plurality of network connection devices are connected, wherein when a failure occurs in the network connection device, failure information is graphically presented to a network administrator, A network management method characterized by urging the user to grasp the status and performing a failure recovery operation on the network device in which a failure has occurred by remote control. 2. In order to manage the network, the MIB information, the setting information and the management method of the connected device are held as one object for each connected device, and based on the connection relationship between the server, the client and the connected device which form the network. On the network configuration diagram drawn by the above, the status symbol generated based on the information of the object is generated and displayed and presented to the network administrator, and when the failure information is received from the connected device, the failure information is displayed. Updating the information of the object based on the updated object, displaying the status of the connected device based on the updated object by generating a status symbol, and connecting the connected device based on the displayed information. The network management method according to claim 1, wherein the failure recovery operation is performed for 3. The network management method according to claim 2, wherein when the status symbol is also displayed on the network configuration diagram, an alarm is displayed when the failure information is received. 4. The network management method according to claim 3, wherein the alarm display blinks in yellow on the display screen. 5. The information displayed by pulling out the MIB information and the setting information from the information of the object of the device by operating the status symbol when the failure occurred in the network is recovered. 3. The network management method according to claim 1, wherein a message for changing the setting for the connected device is created on the display screen based on the information of the object, and the message is transmitted to the device. 6. The network management method according to claim 2, wherein a symbol simulating a traffic sign is used as the status symbol. 7. A transmission / reception means for transmitting / receiving a message to / from a connection device connected to a network, and information of various formats and contents obtainable from the connection device converted into a uniform format as an object. Object management means for managing; status display means for presenting the operating status of the connection device to the network administrator by graphical information based on the object; and the operation status of the connection device displayed by the status display means. A network management system comprising: an instruction operation unit that performs an instruction operation on a connected device to change the object and the graphical information. 8. The state display means uses a configuration diagram display means for displaying a connection relationship between connected devices forming the network as a network configuration diagram, and the object managed by the object management means. The network management system according to claim 7, further comprising: a symbol generation unit that generates a state symbol that represents a state of the connected device; and a symbol presentation unit that presents the state symbol generated by the symbol generation unit to the network administrator. 9. The instruction operation means, when failure information is input from a connected device, converts the failure information into graphical information and presents it to a network administrator, and the symbol presentation means. The status symbol changing means for grasping the status of the equipment of the network by the symbol presented by, changing the setting of the connected equipment based on the object, and changing the display of the status symbol, and the status symbol changing means. 9. The network management system according to claim 7, further comprising a message generation unit that generates a message for restoration processing for the connected device based on the display of the changed status symbol and transfers the message to the transmission / reception unit. 10. The fault information presenting means, when presenting fault information to the network administrator,
The network management system according to claim 9, further comprising alarm means for displaying an alarm. 11. The network management system according to claim 7, wherein the symbol presenting means uses a symbol simulating a traffic sign as the status symbol. 12. The network management system according to claim 7, wherein the object management unit includes an information holding unit that holds MIB information, performance information, setting information, or network service usage status information for each of the connected devices.