JPH11355340A - Network system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change the setting of the configuration of domain automatically in response to a communication state. SOLUTION: Each machine connected to a network in this network system has a control system. In the case that a reply time of a domain server exceeds an object reply time, a comparison discrimination section 23 in the control system decreases gradually a window size to discriminate whether or not the reply time of the domain server is shorter than the object reply time. When the reply time of the domain server still exceeds the object reply time regardless of decreasing the window size, the section 23 discriminates the communication state to be bad, raises a backup domain server to the domain server and demotes the original domain server to the backup domain server automatically. After that, the section 23 discriminates whether or not the reply time of the server demoted to the backup domain server is shorter than the object reply time, and automatically returns the demoted server to the domain server when its reply time is shorter than the object reply time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technique for separating and integrating domains, which are management groups on a network.

[0002]

2. Description of the Related Art A network system has been proposed in which a virtual management group called a domain is set in order to identify individual computers connected to a network, and computers in each domain are managed for each domain. In each domain, a plurality of client machines and a server for managing these client machines are provided. When performing data communication between different domains or within a domain, first, a confirmation signal is sent to the server, the server returns a response to the confirmation signal, and then data communication is performed.

[0003]

In this type of conventional network system, the domain setting is mainly performed manually. Therefore, when there is a low-speed line route or a line with poor line quality in the network, the domain is set. Data cannot be exchanged with a server in the domain, and data communication cannot be performed with each machine (computer) in the domain.

In such a case, conventionally, a system administrator goes to the site and actually inspects the communication state of the network, and performs a process of manually dividing a problem domain. For this reason, there has been a problem that it takes time until the network is restored, and management costs such as labor costs of a system administrator increase.

[0005] The present invention has been made in view of such a point, and an object of the present invention is to provide a network system capable of automatically changing the configuration of a domain according to a communication state. .

[0006]

According to an aspect of the present invention, at least one client machine and each client machine are provided in a domain which is a management group on a network. In a network system provided with a server to manage, in the domain, at least one spare server that can be the server is provided, and response time measuring means for measuring a response time of the server during data communication; Server setting change means for determining whether or not to change the spare server to the server based on the response time.

The "response time measuring means" in claim 1 corresponds to the measuring section 22 in FIG. 1, and the "server setting changing means" corresponds to the comparing and judging section 23 in FIG.

[0008] "Communication parameter changing means" of claim 2
Corresponds to the setting change unit 24 in FIG.

According to a fourth aspect of the present invention, the "first number measuring means" is
Corresponds to the counter.

The "server return determination means" in claim 5 corresponds to the processing in steps S11 to S14 in FIG.

According to a sixth aspect of the present invention, the “second number measuring means” is
Corresponds to the counter.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a network system according to the present invention will be specifically described with reference to the drawings.

FIG. 1 is a schematic block diagram of a control system of a network system according to the present invention. The control system in FIG. 1 is normally realized by software, but may be partially or entirely configured by hardware.

FIG. 2 is an overall configuration diagram of the network system. Hereinafter, before describing the configuration and operation of the control system in FIG. 1, first, the overall configuration of the network will be described with reference to FIG. 2.

The network system shown in FIG.
The example which performs data communication between a section and C section is shown.
Section A includes a client group 1 including a plurality of client machines 11 to 1n, and a domain server 2 that manages the client group 1. Section B and C
Each section has multiple client machines 11-1
n, and a backup domain server 5, which can replace the domain server.
6 are provided.

Sections A and B are connected by a high-speed LAN 7
The section and the section C are connected via the LAN connection device 8. L
Assuming that the line 9 between the AN connecting devices 8 is slow, the section C may not be able to enter the domain constituted by the sections A and B. Therefore, in the present embodiment, the domain server 2 connected to the network
Domain server 3 and client machines 11 to
1n is provided with the control system of FIG. 1 so that the domain configuration can be automatically changed according to the communication state.

As shown in FIG. 1, the control system of each machine (computer) connected to the network includes a network control unit 21, a measurement unit 22, a comparison judgment unit 23
, A setting change unit 24, and a domain information table 25. The network control unit 21 controls the measurement unit 22, the comparison determination unit 23, and the setting change unit 24.
(Operating system).

The measuring unit 22 measures the time from when the confirmation signal is transmitted to the domain server 2 until the response signal is returned. The comparison / determination unit 23 performs a domain division / integration process based on the measurement result by the measurement unit 22 as described later in detail. As will be described in detail later, the setting change unit 24 changes a window size indicating the amount of data to be transmitted at one time and a set value of a retry timer indicating the number of retries at the time of a communication error.

As schematically shown in FIG. 3, the domain information table 25 stores various types of information on machine types, host names, and domain names. FIG. 3 shows the domain information of only the domain server and the backup domain server. However, the domain information of the client machine may be stored in the domain information table 25. Specifically, the domain information table 25 is stored in a recording device such as a hard disk or a nonvolatile memory such as an EEPROM.

FIGS. 4 and 5 are flowcharts showing the processing of the comparing and judging section 23. First, as shown in step S1 of FIG. 4, it is determined whether or not itself is the domain server 2. Here, based on the domain information table 25 of FIG.
It is determined whether or not itself is the domain server 2. If the server itself is the domain server 2, the process proceeds to step S2, and a confirmation response is transmitted to the partner that transmitted the confirmation signal.

On the other hand, if it is determined in step S1 that the server is not the domain server 2, the flow advances to step S3 to determine whether or not the server itself is a backup domain server. If it is a backup domain server, the process proceeds to step S4, and it is determined whether the D counter is (-1). This D counter is a counter that measures the number of times that the response time (reception time−transmission time) of the domain server 2 exceeds the target response time.
Communication with the server is not possible and backup the domain server 2
This is the case when demoted to a domain server. This D counter is provided in the measuring unit 22 of FIG.

If the D counter is not (-1), step S
Proceeding to 5, it is determined whether or not the count value of the D counter is smaller than a predetermined maximum value Dmax. If the count value of the D counter is equal to or greater than the maximum value Dmax, the process proceeds to step S6, where it is determined that communication with the current domain server 2 is not possible, and the backup domain server is determined based on the domain information table 25 in FIG. While being promoted to the server 2, the D counter is set to (-1).

If it is determined in step S5 that the count value of the D counter is smaller than the maximum value Dmax, the process proceeds to step S7, in which it is determined whether the response time To of the domain server 2 is longer than a predetermined target response time Tm. I do.
If the response time To is longer than the target response time Tm, the process proceeds to step S8 to change the window size and the set value of the retry timer. Specifically, the window size is reduced to reduce the amount of data to be transmitted at one time, and the set value of the retry timer is increased by one.

Next, as shown in step S9, the count value of the D counter is increased by one. Next, as shown in step S10, a confirmation transmission is performed to the current domain server 2.

In step S7, the domain server 2
If the response time To is determined to be equal to or less than the target response time Tm, it is determined that normal communication with the current domain server 2 can be performed, and the process ends.

On the other hand, if it is determined in step S4 that the count value of the D counter is (-1), the flow advances to step S11 shown in FIG. 5 to determine whether the count value of the B counter is smaller than a predetermined maximum value Bmax. Is determined. The B counter is a counter that measures the number of times that the response time of the server demoted from the domain server 2 to the backup domain server 2 is shorter than the target response time. This B counter is also provided in the measuring unit 22 of FIG.

If the count value of the B counter is equal to or greater than the maximum value Bmax, it is determined that the communication state has been improved, and step S
Proceeding to 12, the current domain server 2 is demoted to the backup domain, and the server once demoted to the backup domain server is re-transferred to the domain server 2.
To return to. At the same time, the B counter and the D counter are initialized.

If it is determined in step S11 that the count value of the B counter is smaller than the maximum value Bmax, the flow advances to step S13 to determine whether the response time To of the server demoted to the backup domain server is smaller than the target response time Tm. Determine whether or not. The response time To is equal to the target response time Tm.
If so, the process proceeds to step S10 in FIG. If the response time To is smaller than the target response time Tm, the process proceeds to step S14 to increase the count value of the B counter by 1, and then proceeds to step S10 in FIG.
To send a confirmation transmission to the current domain server 2.

On the other hand, if it is determined in step S3 in FIG. 4 that the client is not the backup domain server, it is determined that the client is a client machine, and the process proceeds to step S15 in FIG. In step S15, it is determined whether or not the count value of the D counter is smaller than a predetermined maximum value Dmax. If the count value of the D counter is equal to or greater than the maximum value Dmax, the process proceeds to step S16, where it is determined that communication with the domain server 2 is not possible, and the backup domain server is assigned to the domain server 2 based on the domain information table of FIG. It is promoted and the count value of the D counter is initialized to zero.

If it is determined in step S15 that the count value of the D counter is smaller than the maximum value Dmax, the process proceeds to step S17, where the response time To of the domain server 2 is determined.
Is larger than the target response time Tm. If the response time To is longer than the target response time Tm, step S18
To decrease the window size and increase the set value of the retry timer by one. Next, as shown in step S19, the count value of the D counter is increased by one.

When the processing in steps S16 and S19 is completed, or when the response time To of the domain server 2 is determined to be equal to or less than the target response time Tm in step S17, as shown in step S20, the current Confirmation transmission is performed to the domain server 2.

FIG. 6 is a flowchart of the setting change section 24. First, as shown in step S51 of FIG. 6, it is determined whether the window size is larger than a predetermined minimum size minW. Window size is minimum size minW
If it is larger, the process proceeds to step S52, and the window size is reduced by one unit. However, if the window size is equal to the minimum size, do not reduce it below.

If it is determined in step S51 that the window size is equal to or smaller than the minimum size minW, or if the processing in step S52 has been completed, the flow advances to step S53 to determine whether the value of the retry timer is smaller than a predetermined maximum value maxT. Determine whether or not. If the set value of the retry timer is smaller than the maximum value maxT, the process proceeds to step S54, and the value of the retry timer is increased by one. However, when the set value of the retry timer matches the maximum value maxT, the value is not increased any more.

As described above, in this embodiment, when the response time of the domain server 2 exceeds the target response time, the window size is gradually reduced to make the response time of the domain server 2 shorter than the target response time. Is determined. If the response time of the domain server 2 does not fall within the target response time even if the window size is reduced, it is determined that the communication state is bad and the backup domain server is automatically promoted to the domain server 2 and the original domain is restored. Demote server 2 to a backup domain server.

Thereafter, it is determined whether or not the response time of the server demoted to the backup domain server has become shorter than the target response time.
The domain server 2 is automatically returned.

By performing such processing, it is possible to quickly divide and integrate domains according to the communication state, and even if a network includes a low-speed line path or a path with poor line quality, Data communication can be normally continued.

In this embodiment, since the setting of the domain is automatically changed in accordance with the communication state, the management of the domain is changed as compared with the conventional case where the system administrator mainly changes the setting of the domain manually. Costs can be significantly reduced.

In FIG. 1, an example has been described in which a backup domain server that can be the domain server 2 is distinguished from a client machine. However, the client machine may be a domain server.

In steps S15 to S20 of FIG. 5, when the self is determined to be the client machine, the domain server 2 is determined by the count value of the D counter.
When the communication state becomes good, a process of returning the server once demoted to the backup domain server to the domain server may be added.

[0040]

As described above in detail, according to the present invention, it is determined whether or not to change the spare server to the server based on the response time of the server. Even if a route or a route with poor line quality is included, the domain configuration can be arbitrarily changed according to the communication state. Further, according to the present invention, since the server setting is quickly changed in accordance with the communication state, even if the communication state temporarily deteriorates, data communication can always be continued in a stable state.

Further, according to the present invention, the domain is automatically divided and integrated by changing the server, so that the system administrator does not need to manually change the domain setting, and the management cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a control system of a network system according to the present invention.

FIG. 2 is an overall configuration diagram of a network system according to the present invention.

FIG. 3 is a configuration diagram of a domain information table.

FIG. 4 is a flowchart illustrating processing of a comparison determination unit.

FIG. 5 is a flowchart following FIG. 4;

FIG. 6 is a flowchart of a setting change unit.

[Explanation of symbols]

 Reference Signs List 1 client machine 2 domain server 3, 4 client group 5, 6 backup domain server 7 high-speed LAN 8 LAN connection device 9 line 21 network control unit 22 measurement unit 23 comparison judgment unit 24 setting change unit 25 domain information table

Claims (7)

[Claims] At least one client machine in a domain, which is a management group on a network,
In a network system provided with a server that manages each client machine, at least one spare server that can be the server is provided in the domain, and a response time measuring unit that measures a response time of the server during data communication And a server setting change unit that determines whether to change the spare server to the server based on the measured response time. 2. The server setting change unit, wherein the communication unit includes a communication parameter change unit that changes a communication parameter during data communication with the server when a response time measured by the response time measurement unit exceeds a predetermined time. 2. The network according to claim 1, wherein the controller determines whether to change the spare server to the server based on a response time measured by the response time measuring unit after the communication parameter is changed. system. 3. The network system according to claim 2, wherein the communication parameters include at least a window size representing an amount of data to be transmitted at one time and a number of retries at the time of a communication error. 4. A server according to claim 1, further comprising: first number measuring means for counting the number of times that the response time of the server measured by the response time measuring means exceeds a predetermined time; 4. The network system according to claim 1, wherein when the number of times exceeds a predetermined number, the spare server is changed to the server. 5. After changing the spare server to the server, it is determined whether to return the original server to the server based on the response time of the original server measured by the response time measuring means. The network system according to any one of claims 1 to 4, further comprising a server return determination unit that performs the operation. 6. A second number counting means for counting the number of times that the response time of the original server measured by the response time measuring means is within a predetermined time, wherein the server return determination means comprises 6. The network system according to claim 5, wherein when the number of times exceeds a predetermined number, the original server is returned to the server. 7. A storage means for storing a domain information table showing a relationship among a type, a host name, and a domain name of the server and the spare server in the domain, wherein the server setting change means comprises: The network system according to any one of claims 1 to 6, wherein the server and the spare server are identified on the basis of the information.