JP3177875B2 - Communication method with network connection device via gateway device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a method in which a device in a LAN (local area network) communicates with a network connection device via a plurality of gateway devices and a network.

[0002]

2. Description of the Related Art FIG. 4 is a diagram showing an example of a communication network via a conventional gateway device. In FIG. 4, 1
a, 1b, and 1c are # 1, # 2, and # 3 gateway devices (hereinafter, referred to as # 1, # 2, and # 3 GW), respectively, and 3 is a network (network) such as a telephone network, a line network, and a packet switching network. 4a ₁ to 4A _n is # 1GW1a the # 1 n pieces of network connection devices belonging to the group, 4b ₁ ~4b _n is # 2GW1
n network connection devices belonging to group # 2 of b, 4c ₁ to
4c _n is n network connection devices belonging to the # 3 group of the # 3 GW 1c, 5a to 5d are four devices in the same LAN, 6
Is a LAN.

As shown in FIG. 4, a conventional LAN device and a network connection device are connected to each other via a plurality of gateway devices via a network. The plurality of network connection devices are divided into several groups. The gateway device responsible for communication processing has been defined. When a device in a LAN communicates with a network connection device belonging to a certain group, it is necessary to always communicate via a gateway device assigned to the group. For example any of the network connection device 3a ₁ to 3 A _n belonging to the group of # 1GW1a is, L
When communicating with the device in the AN, the communication must be performed via the # 1 GW 1 a.

[0004]

However, in the conventional communication method with a network connection device via a gateway device,
There were the following problems. It is necessary to set the correspondence between the gateway device and the network connection device to which the network connection device belongs for each group to which the network connection device belongs, and every time the network connection device is added or removed, the device within the LAN is required. However, there is a problem that it is necessary to change the correspondence set in the above. Also, since the number of gateway devices that can be connected in parallel (hereinafter referred to as the number of connections) is limited,
When connections are concentrated on one gateway device, there is a problem that communication cannot be performed regardless of whether there is an empty connection in another gateway device. If one gateway device fails,
Even if the other gateway device is normal, there is a problem that communication with the network connection device assigned to the failed gateway device becomes impossible.

[0005]

According to the present invention, there is provided a method of communicating with a network connection device via a gateway device according to the present invention. , wherein the plurality of gateway devices holds the free connection number information of the own apparatus, respectively, information of free connection number of other gateway devices by performing communication between the gateway device to each other a predetermined cycle T ₁ When a plurality of gateway devices receive a connection request with a network connection device from a device in the LAN, the plurality of gateway devices compare the plurality of free connections that are the held information and have the largest number of free connections. The gateway device is identified, and if the identification result is its own device, the own device performs connection processing, and the identification result is If it is a gateway device in which to perform the connection processing to the destination gateway device forwards the connection request to another gateway apparatus the identification.

According to the present invention, in a method for communicating between a LAN device and a network connection device via a plurality of gateway devices and a network, each of the plurality of gateway devices may be respectively operated by an information holding process of the number of free connections. holds the free connection number information of the own apparatus, the free connection number information other gateway device acquires held by communication between the gateway device to each other a predetermined cycle T _1, the connection process, When each of the plurality of gateway devices receives a connection request with a network connection device from a device in the LAN, the plurality of gateway devices identify the gateway device having the largest number of vacant connections by comparing the plurality of vacant connections as the held information. If the identification result is that of the own device, the own device performs a connection process, and Is a different gateway device, the connection request is transferred to the identified other gateway device to cause the transfer destination gateway device to perform a connection process, so that the device in the LAN communicates with the network connection device. The connection between the conventional network connection device and the gateway device has been lost, so that a connection request can be made to any gateway device. The connection process is performed sequentially from the gateway device having the largest number of connections, the number of connections of each gateway device is averaged, and the communication between the device in the LAN and the network connection device without connection is performed until the number of free connections of all gateway devices reaches zero. Impossibility does not occur.

[0007]

FIG. 1 is a diagram showing an example of a communication network via a gateway device according to the present invention, wherein 3 to 6 in FIG. 1 are the same as those in FIG. The configuration of the network system of FIG. 1 that differs from that of FIG. First
Are # 1, # 2, # 3 GWs 1a, 1b, 1c
Each has therein information 2a, 2b, and 2c of the number of connectable devices (hereinafter referred to as the number of free connections) of its own device and another gateway device. by performing communication between the gateway device to each other each time the T _1), is to keep updating the retained information always new information.
The second different point is that the conventional method of classifying the network connection devices into a plurality of groups and eliminating the correspondence between each network connection device in the divided group and a specific gateway device are abolished. Therefore, as long as the number of free connections of all the gateway devices does not become zero, the devices in the LAN can communicate with a desired network connection device through any of the gateway devices.

Embodiment 1 FIG. 2 is a diagram for explaining a first embodiment of the communication method using the network of FIG. 1. The first embodiment aims at averaging the number of connections of each gateway device and minimizing occurrence of communication failure due to no connection. It is. Now, it is assumed that the number of free connections of each gateway device is [4] for # 1GW1a, [1] for # 2GW1b, and [2] for # 3GW1c. And each gateway device holds the free connection number information of the own apparatus, respectively, information of the number of free connections the fixed period T ₁ every other two gateway devices by performing communication between the gateway device to each other Get and hold. Therefore, it is also possible to compare the magnitude relationship between the three vacant connections, which is the held information.

At time t ₁ in FIG. 2, the # ₁ GW _{1 a}
When the connection request is received from the internal device, the # 1 GW 1a compares the size relationship between the number of available connections [4], [1], and [2] of its own device and the other gateway devices at this time, and compares the three gateway devices. It recognizes that its own device has the largest number of vacant connections, and performs its own connection process with the designated network connection device (see C1 in FIG. 2). # GW1a is connection process C1
Immediately, the number of vacant connections in the own device becomes 1
It broadcasts (delivers the same information to a plurality of terminals) the LAN device and the other gateway devices that the number has decreased to [3] (see C2 in FIG. 2). By this broadcast communication, devices in the LAN and # 1, # 2, # 3GW1a,
1b and 1c recognize that the number of free connections of each gateway device has become [3], [1], and [2].

At the next time t ₂ , when the # ₂ GW 1 b receives a connection request from a device in the LAN, the number of free connections [3] of each gateway device at this time,
By comparing [1] and [2], it is recognized that # 1GW1a has the largest number of vacant connections among the gateway devices, and a connection request from a device in the LAN is transferred to # 1GW1a (FIG. 2 C3, hereinafter C3 is referred to as a path change process). The # 2 GW 1b notifies the LAN device that the subsequent communication is to be performed via the # 1 GW 1a by this route change process (see C4 in FIG. 2). # 1
The GW 1a performs a connection process with the network connection device specified by the connection request received from the # 2 GW 1b (C5 in FIG. 2).
), And the number of free connections of its own device is 1.
Then, the fact that the number has decreased to [2] is broadcast to the LAN device and the other gateway devices (see C6 in FIG. 2). By this broadcast communication, devices in the LAN and # 1 to # 3
The GWs 1a to 1c recognize that the number of free connections of each gateway device has become [2], [1], and [2].

Next, at time t ₃ , if the communication between the # 1 GW 1 a and the network connection device ends and the communication line is disconnected, at this time, the # 1 GW 1 a increases the number of free connections of its own device by one. LAN [3]
Broadcast to internal devices and other gateway devices (Fig. 2
C7). Thus each gateway device, when the free connection number of the own apparatus is changed, with broadcasts it to other devices, since the communication between devices mutually each of the constant period T _1, LAN The internal device and each gateway device can always recognize the latest number of free connections of all gateway devices.

The in-LAN device that has received the information on the number of vacant connections of each gateway device uses this information to communicate subsequent communication information via the gateway device with the largest number of vacant connections. Can be In addition, a connection request can be transmitted to an arbitrary gateway device in expectation of the function of averaging the number of connections by the gateway device without using the information. In any of the above cases, according to the first embodiment, as a result, the number of connections of each gateway device is averaged, and until the number of free connections of all gateway devices reaches zero, the number of connections in the LAN due to no connection is reduced. Communication failure with the network connection device will not occur.

Embodiment 2 FIG. FIG. 3 is a diagram for explaining a second embodiment of the communication method using the network of FIG. 1. In the second embodiment, when a failure occurs in a certain gateway device and a related network, the failure is backed up to improve the reliability of the network. It is a measure. Embodiment 2
In the above, when a failure occurs in a gateway device, a device in a LAN is provided at a predetermined period (this period is now T ₂ ) so that the device in the LAN can automatically recognize which gateway device has a failure. The information on the number of free connections is transmitted to each gateway device. In this information transmission, the communication in which the number of vacant connections is mutually communicated between the gateway devices at regular intervals T1 in the _first embodiment is also transmitted to the devices in the LAN as broadcast communication, and this transmission information is used. You may. Accordingly, the cycle T ₂ for failure check may be the same time as the cycle T ₁ for mutually communicating the number of vacant connections between the gateway devices. In general, the frequency of failure is small, so the cycle T ₂ is longer than T ₁ . May be set for a long time.
For example, a signal obtained by dividing the signal of the cycle T ₁ several times is represented by a cycle T ₂
May be obtained.

In FIG. 3, t ₁ and t ₂ are times for each of the failure checking periods T _2.
The internal device causes each gateway device to transmit information on the number of free connections. Therefore, when each gateway device is operating normally, the devices in the LAN can recognize the number of free connections of each gateway device (FIG. 3).
D1 and D2). Simultaneously with the above t ₁ and t ₂ ,
The device in the LAN uses a timer time T ₃ set in advance.
(Where T ₃ is a time longer than the period T ₂ ), and each gateway device starts the period T ₂
Each time, it is monitored whether or not information on the number of free connections is normally received (see D3 and D4 in FIG. 3). The gateway device receives the signal can not be obtained even after the timer time T ₃ has passed the period T ₂ are recognized as faulty.

In the example of FIG. 3, the device in the LAN can normally receive the information on the number of free connections from all the gateway devices at the time t ₂ , but counts the time from the time t ₂ and counts the timer time T ₃ (the above-mentioned period). even after T ₂ time obtained by adding a predetermined time ΔT in), since the received signal is not obtained from # 1GW1a, # 1GW1a is recognized as a failure by timeout, the number of free connections of the gateway device [ 0] (see D5 in FIG. 3). Then, in the LAN device, the subsequent communication information is # 2GW1b or # 3G except for # 1GW1a recognized as a failure.
Communication with the network connection device is performed via W1c.

According to the second embodiment, as described above, a failed gateway device can be automatically recognized, and communication with a network connection device can be performed via another gateway device excluding the failed gateway device. The time of disability can be reduced, and the reliability of the network can be improved.

[0017]

As described above, according to the present invention, in a method for communicating between a LAN device and a network connection device via a plurality of gateway devices and a network, the method for holding information on the number of free connections includes each gateway device holds the information of free connection number for each own device, acquiring the holding of free connection number information other gateway device by performing communication between the gateway device to each other a predetermined cycle T ₁ In the connection processing step, when each of the plurality of gateway devices receives a connection request with a network connection device from a device in the LAN, the plurality of gateway devices compare the plurality of free connection numbers which are the held information, and The gateway device with the largest is identified, and if the identification result is its own device, the own device performs connection processing. If the identification result is another gateway device, the connection request is transferred to the identified other gateway device and the transfer destination gateway device performs connection processing. When communicating with a device, the conventional network connection device and the gateway device no longer have a corresponding relationship, so a connection request may be made to any gateway device. The connection process is performed sequentially from the gateway device having a large number of vacant connections, the number of connections of each gateway device is averaged, and the LA due to no connection is maintained until the number of vacant connections of all gateway devices reaches zero.
There is an effect that communication failure between the internal device and the network connection device does not occur.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a communication network via a gateway device according to the present invention.

FIG. 2 is a diagram illustrating Embodiment 1 of a communication method using the network in FIG. 1;

FIG. 3 is a diagram illustrating Embodiment 2 of the communication method using the network in FIG. 1;

FIG. 4 is a diagram illustrating an example of a communication network via a conventional gateway device.

[Description of Reference Numerals] 1a, 1b, 1c # 1, # 2, # 3 gateway device 2a, 2b, 2c # 1, # 2, # 3 free connection number information 3 network 4a ₁ ~4c _n network connection device 5a~ 5d LAN device 6 LAN

Claims (4)

(57) [Claims] 1. A method for performing communication between a LAN device and a network connection device via a plurality of gateway devices and a network, wherein each of the plurality of gateway devices holds information on the number of free connections of its own device. with constant by performing communication between the period T ₁ the gateway every mutually get hold of free connection number information of another gateway device, wherein the plurality of gateway devices, from the intra-LAN device and network connection device Upon receiving the connection request, the gateway device having the largest number of free connections is identified by comparing the plurality of free connections, which is the held information, and if the identification result is the own device, the own device is determined. Perform connection processing, and if the identification result is another gateway apparatus, connect to the identified other gateway apparatus. Communication method between network connection device via the gateway device, characterized in that to perform the connection processing to the destination gateway device forwards the determined. 2. A method of performing communication between a LAN device and a network connection device via a plurality of gateway devices and a network, wherein each of the plurality of gateway devices holds information on the number of free connections of its own device. with constant by performing communication between the period T ₁ the gateway every mutually get hold of free connection number information of another gateway device, wherein the plurality of gateway devices, from the intra-LAN device and network connection device Upon receiving the connection request, the gateway device having the largest number of free connections is identified by comparing the plurality of free connections, which is the held information, and if the identification result is the own device, the own device is determined. Perform connection processing, and if the identification result is another gateway apparatus, connect to the identified other gateway apparatus. Request to transfer the request to the gateway device of the transfer destination, and notify the device in the LAN of the connection request source to the gateway device of the transfer destination. A method for communicating with a network connection device via a gateway device, wherein the communication information is communicated with the network connection device via the transfer destination gateway device. 3. A method for performing communication between a device in a LAN and a network connection device via a plurality of gateway devices and a network, wherein each of the plurality of gateway devices holds information on the number of free connections of its own device. with a constant period T to notify a free connection number information of the own apparatus to a LAN within the device and other gateway every _2, the intra-LAN device and the number of unused connections from each gateway device for each of the constant period T ₂ information monitors whether or not notified, the constant when the period T ₂ even after the lapse of a predetermined time period exceeding had notified not the gateway device of the free connection number information, the free connection number of the corresponding gateway device Is recognized as zero, and the subsequent communication information is transmitted to the network connection device through another gateway device except the corresponding gateway device. Communication method between network connection device via the gateway device and performs communication. 4. The gateway device according to claim 3, wherein the fixed period T ₂ is a time longer than the fixed period T _{1 according} to the first embodiment or approximately equal to the fixed period T _1. Communication method with the network connection device via the Internet.