JP2000099429A - Method and device for discriminating network connecting state - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for discriminating network connecting state with which a terminal can independently discriminate the condition of a connection to a network. SOLUTION: When an application 20 is setting to use a proxy service, the connection is requested from a proxy connecting part 31 to a proxy server 42 and in the other case, the name solution of a terminal itself or name route server is requested from a name service inquiry part 32 to a name server 43. In this case, when there is a quick response, the condition is discriminated as on-line but when there is no response, it is discriminated as off-line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for determining a network connection state in a terminal.

[0002]

2. Description of the Related Art Terminals connected to the Internet include a server that provides services to other terminals and a client that is directly operated interactively by a user and receives services from the server.

[0003] A terminal connected to the Internet has a function of responding to a response request when a response request is made, as a function of the network layer, regardless of the server or the client. This is a function for mainly diagnosing the operating status of the terminal from the outside.

[0004] The service provided by the server is not always available due to the disconnection of the route or the stoppage of the server. For this reason, the client requests a service from the server, and if the service availability is not notified after a predetermined delay time has elapsed, it is determined that the service is unavailable. Note that the delay time is expected because there is a delay due to passing through the network.

In the use of the Internet, there is a mechanism called a firewall for ensuring security, and a client may be prohibited from directly connecting to a server outside the organization. In a network environment using a firewall, when a client uses a server, the client does not directly connect to the target server, but connects to a proxy server that provides a relay function (proxy service) to the target server.

In the Internet, when using a service provided by a server, it is necessary to specify the server. The server is specified by a numerical value called an IP address assigned to each terminal. Since an IP address is difficult for a human to remember, general application software using the Internet does not use the IP address directly, but uses a name (host name) composed of alphanumeric characters that a human can easily remember.

Generally, a user instructs an application software to perform an operation by a host name, but the application software itself uses a host name and an IP address at a communication stage.
The IP address of the server that actually requests the service is obtained by using a name service that associates with the address. This is called name resolution.

In a network environment using a firewall, application software on a client does not always perform name resolution. Application software that provides a proxy service instead of individual application software may perform name resolution.

[0009] The name service is a distributed system, and the terminal name server manages the host names and IP addresses of a certain range of terminals to provide a name service.
When a request for resolution of a host name outside the range managed by itself is made, a resolution request is made to the highest server on the network (hereinafter referred to as a root name server).

[0010] Depending on the application software, the connection status with the network is online (connected).
It may be desirable to perform different actions depending on whether it is in a state or an offline (disconnected) state. For example, in the case of a WWW browser, an attempt is made to obtain information from a WWW server in the online state, but information obtained when the WWW server was used last time is reused in the offline state.

When the application software on the client in the offline state requires a network service, as a solution on the OS side, a message prompting the user to connect to the network is displayed, and as a result of the operation of the user, the message is displayed. There is a method that makes it unnecessary to determine the network connection state of application software by shifting to the state.

When the application software attempts to determine the connection state with the network, the application software itself needs to determine the connection state by some method. As a method for this, there is a method in which two modes of offline and online are prepared as menu items of the application software, and the mode is switched by allowing the user to select the mode.

[0013]

However, the method of switching the mode by the user has a drawback that the user needs to understand the mode and perform a complicated switching operation.

It is an object of the present invention to provide a network connection state determination method and apparatus which allow a terminal to independently determine a network connection state.

[0015]

According to an aspect of the present invention, there is provided a method for determining the connection state of one terminal to a network on one terminal, comprising the steps of: A response request is made to another terminal installed at a position where the time delay of information transmission can be ignored, and it is determined whether or not one terminal is connected to the network by using the presence or absence of the response. I do.

As described above, when a service on a network is requested, there is a delay due to passing through the network. Therefore, it is necessary to expect a delay time from when the request is accepted to when the availability is notified. Network delays are independent of the physical distance to servers on the network and depend on the performance of each network and how many networks it passes through on the path. This is called a network distance with respect to the physical distance.

FIG. 1 schematically shows an example of a network. The Internet functions as one large network by interconnecting a plurality of networks. In FIG. 1, there are two servers, servers 1 and 2, each belonging to a different network.
Because each network is interconnected,
The client can use either server, but the server 1 belongs to the same network 1 as the client, the network distance is shorter than the server 2, and the response delay is negligible.

In general, when a client requests a service on a server, the response waiting time must be assumed to be equal to or longer than the time at which a response can be made from the farthest server. The setting of the response waiting time depends on the implementation of the OS, but is often set to about 2 minutes or less. If the conditions are the worst, it is not possible to determine whether or not the service can be used until this time finally elapses.

[0019] This is a restriction that all servers are treated equally even though servers that are distant or close in the network coexist in the network. If you only target servers that are guaranteed to be close to the network and that they are guaranteed to exist,
The delay time is so small that its existence can be ignored, and the response waiting time can be set very short.

Considering the use of a service that is guaranteed to exist on the server as described above, if the terminal is online, there should be an immediate response. It can be said that the terminal is offline. This makes it possible to immediately determine the connection state of the terminal to the network.

The invention according to claim 2 is characterized in that a server fixedly installed in a network is used as a terminal to which a response request is issued.

As described above, every terminal always responds to a response request for diagnosis in order to make it possible to investigate the connection state and operation state. When a response request is broadcast in the network and the terminal is online, a response is returned from other terminals in the network all at once. These include terminals that are close to the network, so that the connection state of the terminals to the network can be immediately determined. This is the simplest method.

However, this method has a disadvantage that the traffic in the network is inadvertently increased, and a disadvantage that the broadcast cannot be used in a special connection form such as a dial-up connection.

These problems can be avoided by limiting the response request target to a specific terminal.

There are network services indispensable for using a network in a network, and an IP address of a server which provides these services is always set in a terminal. Although the servers that provide services that are essential are different depending on the OS and the operation mode, routers, name servers, WINS servers, DHCP servers, proxy servers, mail servers, and the like are candidates. Furthermore, these servers are installed at a position close to the terminal on a network. By making a response request to one or more of these, the connection status of the terminal to the network can be immediately determined.

According to a third aspect of the present invention, in order to confirm the existence of the server, a connection request is made to a service that responds immediately, out of services using TCP or services using UDP.

Depending on the OS, even if the above-mentioned server group can be used as a system, an application may not be able to obtain the IP addresses of those servers.
Acquisition of an IP address is indispensable for making a diagnostic response request, and in this case, a diagnostic response request cannot be made.

This problem can be avoided by using a service that can be used directly from an application and that can immediately receive a response from the services provided by the server.

Specifically, DHCP service, BOOT
Does not require the IP address of the server, such as P service,
There is a method of using a service available by broadcasting, or a method of using a service such as a name service that does not require the application to specify the server IP address.

The invention according to claim 4 is characterized in that one of a proxy service and a name service is used.

A name service is not always available in a firewall. This is because there is a proxy server that provides an external connection service (proxy service), and the proxy server performs name resolution in place of each terminal. In other words, if the application uses the Internet, name resolution must be performed somewhere along the route, so if the terminal is connected to the network, either the proxy service or the name service can be used. .

When the user uses the proxy service, it is necessary to set proxy server information in the application, so that the application can always acquire the IP address. Therefore, it is first checked whether or not the proxy server information is set, and if it is set, it is determined by making a response request to the proxy server. If not set, it is determined by making a name resolution request to the name service.

The name service is a distributed system, and the end name server manages the relationship between the terminal name and the IP address in a certain range and provides a name resolution service. Only when the solution cannot be solved by itself, a solution request is made to the root name server on the network.
Conversely, if the name is resolved within a range that can be resolved by the terminal name server (local name server), a response can be obtained immediately.

Specifically, if the name is to be solved for the terminal itself, it is registered in the terminal name server.
If you're online, you'll be guaranteed a quick response.

According to the fifth aspect of the present invention, in order to confirm the existence of a name service, an IP corresponding to a root name server is used.
Attempts to obtain an address.

In a network to which an unspecified number of people connect, such as a dial-up connection provided by a network provider, a terminal cannot have its own unique name.

As described above, the name service is a distributed system, and if the name server at the end cannot resolve itself, it issues a resolution request to the root name server on the network. That is, all name servers know the IP address of the root name server and can resolve the name of the root name server.

Using this, when a name server requests name resolution for the root name server itself, a response can always be obtained immediately if it is online. Thereby, the network connection status of the terminal can be determined.

The above method is an apparatus according to claim 6, that is, an apparatus for judging a connection state of one terminal to a network on one terminal, wherein a time delay of information transmission can be ignored. A network connection state comprising: a response request unit for requesting a response to another terminal installed at the location; and a determination unit for determining whether or not one terminal is connected to the network by using the presence or absence of the response. The determination device or the device according to claim 7, that is, a proxy connection unit for making a connection request to a proxy server, a name server inquiry unit for requesting a name service to a name server, and one of a proxy connection unit and a name server inquiry unit. A control unit for selectively operating and determining from the result whether one terminal is connected to the network. It can be achieved by connection state detecting apparatus.

[0040]

(Embodiment 1) FIG. 2 shows an embodiment of a network connection state discriminating apparatus according to the present invention. In the figure, reference numeral 10 denotes a network connection state discriminating device, which uses response request means 11 for requesting a response to another terminal installed at a position where a time delay of information transmission can be ignored, and whether or not there is a response. The terminal (client) is implemented between the application software 20 and the network on the terminal (client).

FIG. 3 schematically shows a network for explaining the embodiment of the present invention.
N2 is a network, S1 and S2 are servers, C1 and C2
Is a client.

In FIG. 3, the connection state determination device 10 (not shown) on the client C1 is connected to the network N1.
To determine whether the user is online or offline: (1) The response requesting means 11
An ICMP response request is broadcast to the whole. This is a ping 255.255.25 at the user level
This is equivalent to executing 5.255. The IP address of the local network is always "255.255.25
5.255 ", the application 20 does not need any special setting for specifying the network N1. (2) The determining means 12 waits for a response from an arbitrary terminal for a very short time. If there is a response within the waiting time, it can be determined that the device is online. If there is no response, it is determined that the device is offline and the application 20 is notified.

When the client C1 is online, there is a response from all terminals (server S1, client C2) connected to the network N1. In addition,
Since the response request does not reach the network N2, the terminal (server S2) connected to the network N2 does not respond. Since the terminals connected to the network N1 are close to each other in terms of a network, the response delay time is short enough to be ignored.

The above is the method and apparatus according to the first and sixth aspects. (Embodiment 2) When the connection state determination device 10 on the client C1 in FIG. 3 tries to determine whether the network N1 is online or offline, (1) the response request means 11 ICM for S1
P's response request is made. Change the IP address of server S1 to 12
A value of 8.128.128.128 is equivalent to executing ping128.128.128.128 at the user level. (2) The determination means 12 waits for a very short time for a response from the server S1. If there is a response within the waiting time, it can be determined that the device is online. If there is no response, it is determined that the device is offline and the application 20 is notified.

Since the server S1 is close to the network,
The response delay is negligibly short. Unlike Embodiment 1, since the response is only from the server S1, no extra traffic is generated, but the application 20 needs to set the IP address of the server S1 to be used in advance. The method and apparatus according to the second and sixth aspects of the present invention are those in which the IP address of the server S1 needs to be fixed. (Embodiment 3) When the connection state determination device 10 on the client C1 in FIG. 3 tries to determine whether the network N1 is online or offline, (1) the response request means 11 Tel for S1
connection request for TCP to the net service or da
It makes a request to the ytime service by UDP. te
The connection request by TCP to the lnet service is sent to the server S
1 is 128.128.128.128, and telnet128.128.128 at the user level.
This is equivalent to executing 128.128. Also, da
The ytime service is a service that teaches the current time. When a UDP packet having arbitrary contents is sent to port 13, a packet describing the current time is returned to the request source. (2) The determination means 12 waits for a very short time for a response from the server S1. If there is a response within the waiting time, it can be determined that the device is online. If there is no response, it is determined that the device is offline and the application 20 is notified.

The above is the method and apparatus according to the third and sixth aspects. (Embodiment 4) FIG. 4 shows another example of the embodiment of the network connection state judging device of the present invention together with the whole related system. In the figure, reference numeral 30 denotes a network connection state determination device, which includes a proxy connection unit 31 for making a connection request to a proxy server, a name server inquiry unit 32 for requesting a name service to a name server, and a proxy connection unit 31 or a name server inquiry unit. Control unit 3 for selectively operating any one of the terminals 32 and determining whether the terminal is connected to the network based on the result.
3 and is implemented between the application software 20 and the network on the terminal (client).

Upon receiving an inquiry about the connection status from the application software 20, the control unit 33 selects either the proxy connection unit 31 or the name service inquiry unit 32 according to the situation, and selects the proxy server 42 or the proxy server 42 relayed on the network 41. Name server 4
3 and a service request is made. The control unit 33 responds to the application software 20 according to the result of the request.

FIG. 5 is a flowchart showing an example of processing for determining the connection status of the terminal to the network. (1) First, it is checked whether or not the application 20 is set to use the proxy service (step S100). If the setting is to use the proxy service, a connection request is made from the proxy connection unit 31 to the proxy server 42 (the determination result in step S100 is “YE”).
S '' → Step S101) Otherwise, the name service is used. (2) After making a connection request to the proxy server 42, wait for a very short response (Step S101). If the connection completion notification is received within this waiting time, it is determined that the connection is online (the determination result in step S102 is “YES”), and if there is no connection completion notification, the connection is offline. And cancel the connection request (if the result of the determination in step S102 is "
NO "). (3) When using the name service (step S10)
0 is “NO”, and it is checked whether or not the name service was successfully used last time (step S).
103). (4) If the name resolution is successful, it is checked whether the name resolution is further continuous (the determination result of step S103 is ""
YES "→ step S104) If the inquiry is a continuous inquiry (the determination result of step S104 is" YES "),
Assume that you are online.

This is because unnecessary name resolution requests unnecessarily place an unnecessary load on the name server 43 and cause a decrease in the speed of the application itself. If you try to use services on the network continuously,
Since the user is considered to be working continuously,
It is considered that the connection state of the network has not changed. Here, the continuity criterion was set to 10 seconds. (5) When the previous name resolution failed (step S
If the determination result at step 103 is “NO”, or the name resolution is not continuous (the determination result at step S104 is “NO”), the name service inquiry unit 32 requests the name server 43 to resolve the name of the client itself. (Step S105). Here, assuming that the name of the client itself is “client1”, the client requests the name server 43 for an IP address corresponding to “client1”. (6) Finally, wait a very short time for a response from the name service (step S105). Here, the waiting time was 3 seconds. If the name is resolved within this waiting time, it can be determined that the user is online (the determination result in step S106 is "YES"). If no name resolution occurs,
It is determined that the user is offline, and the name resolution request is canceled (the determination result in step S106 is "NO").

The client itself is managed by the local name server 43 used by the client. Therefore, it is guaranteed that the local name server 43 can resolve the name of the client itself without consulting an external server, and the response time to the name resolution request is very short.

In this embodiment, the connection state determining device 3
It is necessary that the information of the client mounting “0” is correctly set in the connection state determination device 30 in advance or that the information can be acquired from the connection state determination device 30.

The above is the method and the device according to the fourth and seventh aspects. (Embodiment 5) FIG. 6 is a flowchart showing another example of the process of determining the connection status of the terminal to the network, and the operations (1), (2),
(3) and (4) are the same as in the fourth embodiment. (5) 'If the previous name resolution has failed (the determination result in step S103 is “NO”) or if the name resolution is not continuous (the determination result in step S104 is “NO”), a name service inquiry is made. The unit 32 requests the name server 43 to resolve the name of the root name server (step S107). Here, an IP address corresponding to the root name server "a.root-servers.net" is requested to the name server 43. (6) Finally, wait a very short time for a response from the name service (step S107). Here, the waiting time was 3 seconds. If the name is resolved within this waiting time, it can be determined that the user is online (the determination result in step S106 is "YES"). If no name resolution occurs,
It is determined that the user is offline, and the name resolution request is canceled (the determination result in step S106 is "NO").

When the local name server 43 is requested to resolve a name of a terminal not managed by itself, the local name server 43 makes an inquiry to a root name server on an external network. In order to make an inquiry, the root name server I
Since the P address is required, the name and the IP address of the root name server are registered in all the local name servers 43.

The connection state determination device 30 informs the local name server 43 of the name of the root name server.
a. root-servers. I corresponding to "net"
When a P address is requested, since it is always registered in the local name server 43, it is guaranteed that the name can be resolved by itself without making contact with an external server. Therefore, the response time to the name resolution request is also very short.

The above is the method and the device according to the fifth and seventh aspects.

[0056]

As described above, according to the first aspect of the present invention,
According to this, it is possible for the terminal to autonomously determine the state of connection to the network and automatically switch the mode by an application. Further, according to the second aspect, the effect of the first aspect can be obtained without applying an extra load to the network and under a special environment such as dial-up. According to the third aspect, the effect of the second aspect can be obtained without depending on the implementation of the OS of the terminal.

According to the fourth aspect, the effect of the third aspect can be obtained without depending on information unique to the network. According to the fifth aspect, the effect of the fourth aspect can be obtained without depending on the information unique to the terminal.

According to claims 6 and 7, claim 1
It is possible to realize a network connection state determination device capable of executing the methods of (5) to (5).

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a network.

FIG. 2 is a diagram showing an example of an embodiment of a network connection state determination device of the present invention.

FIG. 3 is a schematic diagram illustrating an example of a network for describing an embodiment of the present invention;

FIG. 4 is a diagram showing another example of the embodiment of the network connection state determination device of the present invention.

FIG. 5 is a flowchart illustrating an example of a process of determining a connection state of a terminal to a network according to the present invention;

FIG. 6 is a flowchart showing another example of the process of determining the connection status of the terminal to the network according to the present invention.

[Explanation of symbols]

10, 30: network connection state determination device, 11: response request means, 12: determination means, 20: application software, 31: proxy connection unit, 32: name service inquiry unit, 33: control unit, 41: network, 42: Proxy server, 43: name server, N
1, N2: network, S1, S2: server, C1,
C2: Client.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yutaka Managa 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo F-term in Nippon Telegraph and Telephone Corporation (reference) 5B085 AC03 AC12 AC13 AE04 BG07 5B089 GA19 GB01 GB09 HA10 HB02 JB10 KA04 KB06 KC11 KC23 KC44 KC47 KF01 5K033 CB08 DA01 DA06 DB20 EA07 EC03 5K035 AA06 BB03 CC10 DD01 EE07 FF04 KK04

Claims (7)

[Claims] 1. A method for determining, on one terminal, a connection state of the one terminal to a network, wherein the other terminal is located at a position where a time delay of information transmission from one terminal can be ignored. A network connection state determination method, comprising: making a response request to a terminal; and determining whether or not one terminal is connected to a network using the presence or absence of the response. 2. A terminal to which a response request is made,
2. The method according to claim 1, wherein a server fixedly installed in the network is used. 3. Service or UDP using TCP
3. The network connection state determination method according to claim 2, wherein a connection request is made to a service that responds immediately among services that use. 4. The method according to claim 3, wherein one of a proxy service and a name service is used.
The described network connection state determination method. 5. The method according to claim 4, wherein an attempt is made to obtain an IP address corresponding to the root name server. 6. An apparatus for determining, on one terminal, a connection state of the one terminal to a network, wherein a response request is sent to another terminal installed at a position where a time delay of information transmission can be ignored. A network connection state determining device, comprising: a response requesting unit for performing the response; and a determining unit for determining whether one terminal is connected to a network by using the presence or absence of the response. 7. A proxy connection unit for making a connection request to the proxy server, a name server inquiry unit for requesting a name service to the name server, and selectively operating either the proxy connection unit or the name server inquiry unit. 7. The network connection state determination device according to claim 6, further comprising: a control unit configured to determine whether one terminal is connected to a network based on a result.