JP5018931B2 - Node equipment - Google Patents

Description

The present invention relates to a node device, and more particularly to a node device that constitutes a communication system with a terminal or with a terminal and a location registration server device.
Currently, studies on next-generation mobile communication systems are being carried out by research institutions and standardization organizations around the world. The next generation mobile communication system aims to provide multimedia services including high-speed data communication up to about 2Mbps.

In particular, packet communication services such as the Internet are expected to become core services in next-generation mobile communication, instead of services centered on current voice.
Furthermore, a communication system that integrates movement-fixation has been started. In such a mobile-fixed communication system, it is important to reliably transmit a packet from a source terminal to a destination terminal.

A conceptual diagram and problems of a mobile communication packet system currently implemented in cellular communication networks in Japan and Europe are described in the mobile packet communication system described in Japanese Patent Application No. 11-41784 (H11.2.19).
FIG. 32 shows a configuration example of the mobile packet communication system in the above application. This communication system includes location registration server devices 301 and 302 and node devices 201 to 204 each having areas 211 to 214. In the example shown in the figure, a blank with an underscore is provided before the least significant digit of three digits, such as “301” and “30_1”. It will be omitted.

Addresses [ADR1] to [ADR6] are assigned to these devices 301, 302, and 201 to 204, respectively.
Further, this communication system includes mobile terminals (hereinafter simply referred to as terminals) 103, 104, and 101, 102 located in areas 211 to 213, respectively. [1.1.1], [1.1.2], [2.1.1], and [2.2.1] are allocated.

In the figure, the subscriber node and the gate node in the above application are not distinguished from each other and are simply referred to as node devices, and the terminal, node device, and the like are used in a changed form.
The location registration server devices 301 and 302 are installed corresponding to the upper digits of the packet destination address (for example, IPv4 and IPv6), and each associates the terminal with the address of the node device in the area in which it is located. Location registration tables 311 and 312 are provided.

For example, the location registration table 311 includes the addresses [1.1.1] and [1.1.2] of the terminals 101 and 102 whose addresses are [1.XX (X: don't care)] and the node devices 203 in which they are located. Address [ADR5] is associated and registered.
Similarly, the location registration table 312 includes addresses [2.1.1] and [2.2.1] of the terminals 103 and 104 whose addresses are [2.XX] and addresses [ADR3] and [ADR4] of the node devices 201 and 202, respectively. ] Is registered.

The servers 301 and 302 have a function of transferring a packet based on the information in the location registration table.
Each of the node devices 201 to 204 corresponds to a position information table 221 to 224 (only 222 is shown) for storing the address of the terminal and its serving node device, and further from the upper row digit of the destination address of the packet. And a server search table 40 for searching for the address of the location registration server device to be searched.

FIG. 33 shows an example of packet transfer operation in the mobile packet communication system shown in FIG. Hereinafter, the operation when the user packet 71 is transmitted from the terminal 104 to the terminal 101 will be described in the order of processing steps.
Step S1: The terminal 104 transmits a user packet 71 including an address [1.1.1] indicating the address to the terminal 101 to the node device 202.

Step S2: The node device 202 searches the server search table 40 for the address ADR1 of the server 301 corresponding to the address [1.1.1] of the terminal 101.
Step S3: The node device 202 adds the address ADR1 of the server 301 to the received user packet 71 and transfers it to the server 301 as an inter-node packet 81.
Step S4: The server 301 searches the location registration table 311 for the address ADR5 of the node device 203 in the area where the terminal 101 is located.

Step S5: The server 301 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [ADR5] to the node device 203.
Step S6: The server 301 notifies the node device 202 of the address ADR5 of the node device 203 where the terminal 101 is located, based on the transmission source address ADR4 of the packet 81.
Step S7: The node device 203 transmits to the terminal 101 the packet 71 obtained by removing the address ADR5 of the own device from the packet 82, and the terminal 101 receives this.

Step S8: The node device 202 updates or adds the node device address where the terminal 101 is located in the location information table 222 to [ADR5].
Step S9: The next user packet 71 addressed to the terminal 101 arrives at the node device 202.
Step S10: The node device 202 searches the location information table 222 to obtain the address ADR5 of the node device 203 in the area where the terminal 101 is located.

Step S11: The node device 202 directly transfers the inter-node packet 83 to which the address ADR5 of the node device 203 is added to the received packet 71 addressed to the terminal 101, to the node device 203.
Step S12: The node device 203 transmits to the terminal 101 a user packet 71 obtained by removing the address ADR5 from the packet 83 of the node device 203.
As a result, the packets 71 sequentially transmitted from the terminal 104 are received by the terminal 101.

In a communication system configured with such a conventional node device, packet loss occurs when the terminal 101 moves to an area of another node device.
This will be described below with reference to FIG. 34 showing the operation after the packet transfer operation of FIG.
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration for the communication system.

Step S3: The node device 204 searches the server search table 40 for the address ADR1 of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.
Step S5: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [ADR6].

Step S6: The user packet 71 addressed to the terminal 101 arrives at the node device 202.
Step S7: The node device 202 searches the location information table 222 for the address ADR5 of the node device 203 located in the terminal 101.
Step S8: The node device 202 transfers the inter-node packet 81 in which the address ADR5 is added to the received packet 71 addressed to the terminal 101 to the node device 203.

Step S9: The node device 203 cannot transmit the user packet 71 to the terminal 101 because the destination terminal 101 is not located.
Thereafter, each time the terminal 104 transmits a user packet 71 to the terminal 101, steps S6 to S9 are repeated. The user packet 71 is discarded.
As described above, in the conventional mobile packet communication system, when the destination terminal moves and the visited node device changes, the user packet received in the former visited node device cannot be delivered to the destination terminal. Communication quality deteriorates due to packet loss.

Also, since the cached destination terminal location information in the location information table of the transmitting side node device is not updated, packets continue to be forwarded to the former node device even though the destination terminal has already moved. There was a problem.
Therefore, the present invention has the following two problems in a node device that constitutes a communication system with a terminal or with a terminal and a location registration server device.

Problem 1: To eliminate the packet loss that occurs when the destination terminal moves to the area of another node device.
Problem 2: Since the stored location information is not updated in the source node device, the source node device does not continue to transmit packets to the former node device in which the destination terminal was located. .

The node device according to the present invention provides the following two large solutions for the above two problems.
Solution 1 for Problem 1: The node device on the receiving side receives the packet via the location registration server device when the destination terminal of the received packet is not located in its own area. Forward to.

Solution 2 for Problem 1: When a destination terminal node node device moves to its own area, the destination terminal node device directly contacts the old node node device that the destination terminal device was in before moving. Alternatively, the device address is notified through another device.
Solution 1 for Problem 2: The node device on the receiving side transmits the address of the node device in the destination terminal via the location registration server device when the destination terminal of the received packet is not in the area. Notify the original node device.

Solution 2 for Problem 2: When a destination terminal is located in a node device, when the destination terminal moves to its own area, its own device address is sent via the location registration server device, The node device is notified.
In the following, means for solving these problems will be described.
The node device according to the present invention can be connected to either a mobile network or a fixed network.

In addition, the terminals that can be registered can move between fixed network node devices, between mobile network node devices, and between fixed network and mobile network node devices.
The movement of these terminals is described as “the terminal moves from the area of the node device to the area of another node device”.
First, Solution 1 for Problem 1 will be described.

FIG. 1 shows an operation principle of a node device that constitutes a communication system together with a terminal and a location registration server device. The configuration of the communication system is the same as the system configuration shown in FIG.
This operation principle particularly relates to a receiving-side node device that is a destination node device for inter-node packets.
Describing this principle roughly, the receiving-side node device 203 determines that the address of the node device 204 where the destination terminal 101 is located when the destination terminal 101 of the received packet 81 is not located in its own area 213. When it is known, the packet 81 is transferred to the node device 204 in the destination terminal area.

When the node device 203 on the receiving side does not know the address, the packet 81 is directly or indirectly based on the location registration table 311 or indirectly via another device (for example, a source node device or a location registration server device). Transfer to the node device 204 in the destination terminal area.
Next, a detailed operation will be described.
In the figure, the state before the packet transfer operation is that the terminal 101 is located in the area 213 of the node device 203, and the source node device 202 uses the address ADR5 of the node device 203 located in the terminal 101 as location information. It is assumed that it is stored in the table 222.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration for the communication system.
Step S3: The node device 204 searches the server search table 40 to obtain the address ADR1 of the location registration server device 301 corresponding to the address [1.1.1] = [1.XX] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.

Step S5: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [ADR6].
That is, the location registration server device 301 stores the address [1.1.1] of the terminal 101 and the address [ADR6] of the node device 204 in the terminal 101 area in the location registration table 311 in association with each other.
Step S6: The terminal 104 transmits a user packet 71 addressed to the terminal 101 to the node device 202.

Step S7: The node device 202 searches the location information table 222 to obtain the address ADR5 of the node device 203 in the area where the terminal 101 is located.
Step S8: The node device 202 adds the address ADR5 of the node device 203 to the packet 71 and transfers it as an inter-node packet 81.
Step S9: The node device 203 receives the packet 81.

At this time, the node device 203, when the destination terminal 101 is not located in its own area 213, but knows the address [ADR6] of the node device 204 located in the destination terminal 101, sends the packet 81 to the node device 204. Direct transfer.
When the node device 203 does not know the address [ADR6] of the node device 204, the position information registered in the location registration table 311 (the address [1.1.1] of the terminal 101 and the address of the node device in which the terminal 101 is located) Based on the correspondence relationship), the packet 71 addressed to the terminal 101 included in the packet 81 is transferred to the node device 204 in the area where the terminal 101 is located, directly or indirectly via another device.

Through the above operation, the user packet 81 received by the former serving node device 203 before the destination terminal 101 moves is transferred to the visited node device 204 after the movement, thereby preventing communication quality deterioration due to packet loss. It becomes possible.
The user packet 71 is transferred between the node devices by being included in the inter-node packet 81 or the like. Thereafter, the transfer between the node devices is simply referred to as “the user packet 71 is transferred between the node devices. May be stated.

Further, in the above, referring to the location registration table, the received packet can be transferred to the node device in the destination terminal area via the location registration server device.
That is, in the figure, the node device 203 on the receiving side includes the packet 71 in the inter-node packet and transfers it to the location registration server device 301.

The location registration server device 301 refers to the location registration table 311 to obtain the address [ADR6] of the node device 204 in which the destination terminal 101 of the packet 71 is located, and includes the packet 71 in the inter-node packet. Forward to.
In the above, the packet is once returned to the source node device, and the source node device obtains the node device address where the destination terminal is located from the location registration server device, and the packet is sent to the source node device. It can be transferred to the node device in the destination terminal area.

That is, in the figure, when the destination terminal 101 of the received packet 81 (packet 71) is not located in the own device 203, the receiving-side node device 203 returns the packet 71 to the transmission source node device 202.
Receiving this, the source node device 202 knows that the destination terminal 101 of the packet 71 is not located in the receiving side node device, and from the location registration server device 301 to the node device 204 located in the destination terminal 101. The address [ADR6] is acquired and the packet 71 is directly transferred to the node device 204.

In the above, the packet is once returned to the transmission source node device, the transmission source node device transfers the packet to the location registration server device, and the location registration server device stores the location registration table. By referring to the received packet, it is possible to transfer the received packet to the node device in the destination terminal area.
That is, when the packet 71 is returned, the transmission source node device 202 determines that the destination terminal device 101 is not located in the reception-side node device 203, and transmits the packet 71 to the location registration server device 301.
Forward to.

As a result, the source node apparatus 202 entrusts the transfer of the packet 71 to the location registration server apparatus 301 in the same manner as the receiving side node apparatus 203 of claim 2.
In the above description, when the packet is transferred to the transmission source node device, the packet can be further transferred via the location registration server device.
That is, in the figure, when the destination terminal 101 is not located in its own area 213, the receiving-side node device 203 transfers the received packet to the transmission-source node device 202. To ask.

The location registration server device 302 refers to the location registration table and transfers the packet 71 to the node device 202 of the transmission source located in the transmission source terminal 104.
As a result, the receiving-side node device 203 can return the packet 71 to the transmitting node device.
Thereafter, the source node device transfers the packet 71 directly or via the location registration server device to the node device in the destination terminal area.

Further, in the above, it is possible to acquire the address of the node device in the destination terminal area from the location registration server device and transfer the packet to the node device of the address.
That is, in the figure, when the destination terminal device 203 of the received packet 81 (packet 71) is not located in its own area 213, the receiving side node device 203 receives the address of the node device 204 that is located in the destination terminal 101. [ADR6] is inquired of the location registration server device 301, and the packet 71 is transferred to the node device 204 of the acquired address [ADR6], that is, the node device in the destination terminal area.

As a result, the node device on the receiving side can directly transfer the packet to the node device in the destination terminal area even when the destination terminal is not in the area.
In addition, in the above, when having a storage unit that stores the address of the destination terminal in association with the address of the node of the destination terminal, and when the destination terminal of the received packet is not in the area, The packet can be transferred to the node device in the destination terminal area.

That is, the receiving-side node device has a storage unit that stores the address of the destination terminal in association with the address of the node device in the destination terminal area.
When the node device on the receiving side receives an inter-node packet addressed to the destination terminal from the source node device, if the destination terminal is not located in its own area, it is stored in the storage unit (know The packet is forwarded to the node device in the area where the destination terminal is located.

As a result, the node device on the receiving side can directly transfer the packet (inter-node packet) to the node device in the destination terminal area even when the destination terminal is not in the area. Become.
Further, in the above, the transfer of the packet can be continued until a predetermined time elapses after receiving the packet or until an instruction to end the packet transfer is given.

As a result, the receiving-side node device 203 can perform packet transfer until transfer of a packet belonging to a predetermined packet communication is completed.
Furthermore, after the packet transfer is completed, the node device address 204 in the destination terminal area stored in the storage unit may be deleted, and the storage capacity of the storage unit can be reduced.

Next, the node device as the solving means 2 for the problem 1 is the node device that constitutes the communication system together with the terminal. When the destination terminal moves to its own area, The address of the node device in the service area is acquired, and the self-device address and the address of the destination terminal are notified to the node device in the former service area.
FIG. 2 shows an operation principle of the node device according to the present invention which constitutes a communication system together with the terminal and the location registration server device. The configuration of the communication system is the same as the configuration of the communication system in FIG.

Here, the location registration server device is not involved.
In general, this operation principle is based on the fact that the terminal 101 has moved to the area 214 of the node device 204, so that the node device 204 in the terminal area directly or indirectly through another device The local device 203 is notified of its own device address [ADR6], and based on this address [ADR6]
The node device 203 can transfer the received packet 82 (packet 71) to the node device 204.

Next, a detailed operation will be described.
In the figure, as a state before the packet transfer operation, the terminal 101 is located in the area 213 of the node device 203, and the source node device 202 uses the address ADR5 of the node device 203 located in the terminal 101 as location information. It is assumed that it is stored in the table 222.
Step S1: The terminal 101 moves to the area 214 of the node device 204.

Step S2: At this time, it is assumed that the address [ADR5] of the node device 203 in which the destination terminal 101 is formerly located is stored in any communication system (terminal, node device).
Step S3: The terminal 101 performs location registration for the communication system.
Step S4: The node device 204 notifies the former device node A 203 of the own device address ADR6 directly or indirectly using the address ADR5 of the former device node 203.

Step S5: The former node device 203 adds, for example, the address [1.1.1] of the terminal 101 and the address [ADR6] of the node device in the area to the “location information table 223 for“ inter-node packet transfer ”” To do.
With the above operation, the node device 203 in which the destination terminal 101 was located before moving knows the address [ADR6] of the node device 204 in the destination terminal 101 of the received user packet 71.

As a result, the former node device 203 can transfer the packet 71 to the node device located in the destination terminal 101 without discarding the packet 71, and can prevent deterioration in communication quality due to packet loss.
Thereafter, the former node device 203 performs the packet transfer to the node device located in the destination terminal 101 as the node device on the receiving side in the means of claim 1 or 7 of the present invention in the following steps S6 to S10. Perform the action.

Steps S6 to S8: Similar to steps S6 to S8 in FIG. 1, the terminal 104 transmits a packet 71 addressed to the terminal 101, and this packet 71 arrives at the node device 203 as a packet 81.
Step S9: The node device 203 searches the location information table 223 to obtain the address [ADR6] of the node device 204 in the area where the terminal 101 is located (knows the node apparatus where the destination terminal is located).
Step S10: The node device 203 transfers the packet 82 (packet 71) in which the destination address [ADR5] of the received packet 81 is rewritten to [ADR6] to the node device 204.

Also, every time the destination terminal 101 moves to another node device area, the above-mentioned packet transfer continuation operation is performed for a predetermined time , and the node device in the destination terminal area (the new node node device) By notifying the own node address to the node device in the service area, all the former node devices in the existing area transfer the received packet addressed to the destination terminal 101 to the node device in the area next to the current device. .
As a result, packets addressed to the terminal received by all the former node devices are transferred to the new node device.

Further, in the above, a storage unit that stores the address of the node device in which the destination terminal is located is further received, the address stored in the storage unit is received, and the node device in the former location of the address The device address can be notified.
That is, in the figure, the destination terminal 101 has a storage unit 111, and the storage unit 111 stores the address [ADR5] of the node device 203 in which the own device is located.

When the destination terminal 101 moves to its own area 214, the node device 204 located in the terminal receives the address [ADR5] by a notification from the destination terminal 101 (for example, a location registration request) or an inquiry from its own device. To do.
Then, the node device 204 notifies the address device [ADR6] of the own device and the destination terminal address to the former node device 203 of the received address [ADR5].

As a result, the former node device 203 can know the address [ADR5] of the node device 204 in which the destination terminal 101 that has moved out of its own area 213 is located.
Further, in the above, during the communication is continued, the storage unit can store the address of the node device with which the destination terminal has started communication.
That is, the storage unit 111 of the destination terminal 10-1 stores the address [ADR5] of the node device (hereinafter referred to as communication start node device) 203 when communication is started. Then, the node device 204 in the destination terminal area notifies the communication start node device 203 of its own device address [ADR6] and the destination terminal address.

Further, when the destination terminal 101 moves to another node device 205 (not shown, the address is [ADR7]) while communication is continued, the other node device 205 uses the address [ADR5 The local device address [ADR7] is notified to the communication start node device 203.
As a result, every time the destination terminal 101 moves to the area of a new node device, the new node device notifies the communication start node device 203 of its own device address and the destination terminal address. Even if the destination terminal 101 sequentially moves in the area where communication is ongoing, the communication start node device 203 can know the address of the node device in which the destination terminal 101 is currently located.

In addition, in the above, the storage unit stores all the old-area node device addresses that have been in service from the time when the destination terminal started communication to the present time. The node device can be notified of its own device address and the destination terminal address.
That is, in the figure, the storage unit 111 has been in the area from the node device 203 where the destination terminal 101 started communication to the present time, for example, the node device 203 and passed when moving from the node device 203 to the node device 204. For example, all addresses of node devices 206 to 208 (not shown) are stored.

Then, the node device 204 in the destination terminal area notifies the old device address [ADR6] and the destination terminal address to all the former node devices 203 and 206 to 208 in the existing area.
As a result, all the former node devices 203 and 206 to 208 in which the destination terminal 101 is located know the address [ADR6] of the node device 204 in which the destination terminal 101 is located, while communication is continuing. Thus, the received packet addressed to the destination terminal 101 can be transferred without being discarded.

  In addition, in the above, the storage device further includes a storage unit that stores the address of the former node device stored in the storage unit of the destination terminal and the address of the destination terminal in association with each other, and the destination terminal When moving to the area of the newly located node device and the newly located node device notifies the address of its own device, the node device of the former location of the address stored in the storage unit It is possible to notify the own device address and the destination terminal address.

That is, the node device 204 in the destination terminal area stores the old node node address 203 [ADR5] and the destination terminal 101 address stored in the storage unit 111 of the destination terminal 101 in the storage unit (not shown). ).
Then, the destination terminal 101 moves to an area (not shown) of the next newly located node device, and receives a notification of the address and the destination terminal address from the newly located node device.

The node device 204 in the destination terminal area (currently, the destination terminal 101 is not in the area), the node device address in the new area and the destination terminal address of the address [ADR5] stored in the storage unit The node device 203 in the area is notified.
As a result, the former node device 203 can know the address of the new node device in which the destination terminal 101 is located.

  In the above, the communication system further includes a location registration server device, and the location registration server device was registered in the location registration table before location registration when receiving the location registration request from the destination terminal. Based on the address of the former node device, the node device address of the destination terminal and the destination terminal address can be notified to the former node device.

That is, the node device 204 in the destination terminal area makes a location registration request for the destination terminal 101 to the location registration server device 301 when the destination terminal 101 moves to its own area 214.
The location registration server device 301 knows the address of the former node device 203 of the destination terminal 101 from the location registration table 311 before receiving the location registration request and performs the location registration, and this former node device The node device address [ADR6] of the destination terminal and the destination terminal address are notified to 203.

As a result, the former node device 203 can know the address [ADR6] of the node device 204 in the destination terminal area even when the destination terminal 101 moves out of the area of its own area 213.
In addition, in the above, when the location registration server device receives a location registration request of the destination terminal that is continuing communication, the location registration server device does not perform location registration, and the node device to which the destination terminal has started communication has its own device address and The destination terminal address can be notified.

That is, when the location registration server device 301 receives a location registration request for the destination terminal 101 from the node device 204 in the destination terminal area while the destination terminal 101 is continuing communication, the location registration server device 301 does not perform location registration and does not perform location registration. The address of the node device 203 is not updated to the address of the node device 204 in the destination terminal area.
As a result, even when the destination terminal 101 moves in the area of two or more node devices while the communication is continuing, the location registration server device 301 allows the node device 203 with which the destination terminal 101 has started communication.
Will be notified of the address [ADR6].

Thereby, the communication start node device 203 knows the address [ADR6] of the node device 204 in the destination terminal area.
In the above, the communication system further includes a location registration server device, and when the destination terminal has moved to its own area, the destination terminal was located before the location registration of the terminal was performed. The address of the node device in the area can be acquired from the location registration server apparatus, and the own apparatus address and the destination terminal address can be notified to the node apparatus in the former area.

That is, when the destination terminal 101 moves to its own area 214 when the destination terminal 101 moves to its own area 214, the node device 204 located in the destination terminal before the location registration of the destination terminal 101 from the location registration server apparatus 301 Get the device address. Since this address is before location registration, it is the address [ADR5] of the former node device 203.
Accordingly, the node device 204 in the destination terminal area notifies the former device address [ADR6] and the destination terminal address to the former node apparatus 203 in the address [ADR5].

This also makes it possible for the former node device 203 to know the address [ADR6] of the node device 204 in the destination terminal area even when the destination terminal 101 moves out of the area of its own area.
In the above, the communication system includes a location registration server device, and the location registration server device further includes a storage unit that stores an address of the former node device, and receives a location registration request from the destination terminal. Can be notified to the node device in the former area of the location registration.

That is, the location registration server device 301 stores the address [ADR5] of the former node device 203 where the destination terminal 101 is located in the storage unit (not shown).
When the destination terminal 101 moves to its own area 214, the node device 204 in the destination terminal area performs location registration of the destination terminal 101 with respect to the location registration server device 301.
The location registration server apparatus 301 notifies the address [ADR6] of the own apparatus (the node apparatus 204 in the destination terminal area) and the destination terminal address to the former node apparatus 203 in the stored address [ADR5].

As a result, the node device 204 in the destination terminal area has notified the own device address [ADR6] and the destination terminal address to the former node device 203 via the location registration server device 301.
Further, in the above, the communication system has a location registration server device, the location registration server device has a storage unit that stores the address of the former node device, and the destination terminal moves to its own area. Then, the address of the former node device can be received from the location registration server device, and the own device address and the destination terminal address can be notified to the former node device.

That is, the location registration server device 301 stores the address [ADR5] of the former node device 203 where the destination terminal 101 is located in the storage unit (not shown).
Then, when the destination terminal 101 has moved to its own area 214, the node device 204 located in the destination terminal makes an inquiry to the location registration server device 301 or stores it in response to the location registration server device 301 in response to location registration. The node device address [ADR5] of the former location stored in the section is acquired.

Therefore, the node device 204 directly notifies the node device 203 of its own device address [ADR6] and the destination terminal address. Thereby, the node device 203 knows the node device address [ADR6] where the destination terminal 101 is located.
In addition, in the above, the storage unit stores the address of the former node device when the destination terminal starts communication while the destination terminal is continuing communication, and stores the address of the old region when the communication starts. The node device can be notified of its own device address and the destination terminal address.

That is, the storage unit of the location registration server device 301 stores the address [ADR5] of the node device (communication start node device) 203 when the destination terminal 101 starts communication.
Accordingly, the address [ADR6] of the node device 204 and the destination terminal address are notified to the node device 203 via the location registration server device 301 or directly from the node device 204.
As a result, even when the destination terminal sequentially moves in the area where the communication is continuing, the communication start node device 203 knows the node device address where the destination terminal is currently located.

In addition, in the above, the storage unit stores all the former node device addresses in which the destination terminal is located from the start of communication to the present time, and the nodes in the destination terminal are located in all the former node devices. The device address and the destination terminal address can be notified.
That is, the location registration server device 301 stores all the former node device addresses (including the addresses of the communication start node devices) in which the destination terminal 101 has been in service from the start of communication to the current time in the storage unit.

Then, the node device address where the destination terminal is currently located and the destination terminal address are notified to all the formerly located node devices via the location registration server device or directly.
As a result, all the former node devices that have moved while the destination terminal is in communication know the node device address where the destination terminal is currently located.

  Next, a node device as solution 1 for Problem 2 is a node device that constitutes a communication system together with a terminal and a location registration server device, and the destination terminal of the received packet is not located in its own area, and the destination terminal When it knows the address of the node device in which it is located, it notifies the address registration node device of the address by notifying the address to the node device that sent the packet. The node device address in which the destination terminal is located is given to the source node device.

FIG. 3 shows an operation principle of the means 2 for solving the problem 2 that constitutes the communication system together with the terminal and the location registration server device. The configuration of the communication system is the same as the configuration of the communication system in FIG.
Generally speaking, this operating principle is based on the fact that the receiving-side node device 203 has received the inter-node packet 81, and the destination terminal 101 that the device itself knows or the location registration server device 301 has registered. The address [ADR6] of the node device 204 in the service area is notified to the source node device 202.

Next, the detailed operation will be described.
In FIG. 3, as a state before the transfer operation of the packet 71, the transmission source node device 202 stores the address ADR5 of the visited node device 203 of the terminal 101 in the position information table 222. The terminal 101 moves from the area 213 of the node device 203 to the area 214 of the node device 204 to perform location registration, and the address ADR6 of the node device 204 is stored in the location registration table 311 of the location registration server device 301. 1.1.1] and registered.

Step S1: The user packet 71 addressed to the terminal 101 arrives at the node device 202.
Step S2: The node device 202 searches the location information table 222 to obtain the address ADR5 of the node device 203 in the area where the terminal 101 is located.
Step S3: The node device 202 sends an inter-node packet 81 with the address ADR5 of the node device 203 added to the received user packet 71 addressed to the terminal 101.

Step S4: The node device 203 receives the terminal 101 that is the destination of the received packet 81 (packet 71).
Is not located in its own area 213, and if it knows the address [ADR6] of the node device 204 located in the destination terminal 101, it notifies the transmission source node device 202.
If the node device 203 does not know, the node device 203 notifies the transmission source node device 202 directly or indirectly of the address [ADR6] of the node device 204 located in the terminal 101 that is registered in the location registration server device 301.

As a result, the source node device knows the node device in the destination terminal area, and can transfer a packet to the destination node device even when the destination terminal 101 moves. .
In addition, in the above, a storage unit that stores the node device address of the destination terminal is further included, and when the destination terminal of the received packet is not in its own area, the storage unit is referred to The node device address of the destination terminal can be notified to the source node device.

That is, in the figure, the node device 203 on the receiving side stores the node device address [ADR6] in the destination terminal area obtained by receiving from another device in the storage unit (not shown).
Then, when the destination terminal of the received inter-node packet is not located in its own area, the receiving-side node device 203 notifies the address [ADR6] and the destination terminal address to the source node device.

As a result, the source node device 202 knows the address of the node device where the destination terminal 101 is currently located, and transfers the packet to the destination node device even when the destination terminal 101 moves. Can do.
Note that the means described in “Solution 2 for Problem 1” can be used as a means for the node device 203 to store the node device address of the destination terminal.

Further, in the above, the communication system further includes a location registration server device, forwards the received packet to the location registration server device, and transmits the node device address of the destination terminal and the destination terminal address. It is possible to request notification to the original node device.
That is, in the figure, the node device 203 on the receiving side transfers the packet 81 to the location registration server device 301, so that the address [ADR6] of the node device 204 in the destination terminal area and the destination terminal address are transmitted from the transmission source. The node device 202 is requested to be notified.

The location registration server device 301 notifies the address [ADR6] of the node device 204 in the destination terminal area and the destination terminal device 202 of the destination terminal address.
Further, in the above, the communication system further includes a location registration server device, and a message requesting to notify the destination node device address and the destination terminal address of the destination device is sent to the location node It can be transmitted to the registration server device.

That is, when the destination terminal 101 of the packet 81 is not located in its own area 213, the address [ADR6] of the node device located in the destination terminal and the destination terminal address are notified to the source node device 202. To the location registration server device 301.
The location registration server device 301 notifies the source node device 202 of the address [ADR6] and the destination terminal address.

As a result, the source node apparatus 202 knows the address [ADR6] of the node apparatus 204 in which the destination terminal 101 is currently located.
Further, in the above, the communication system further includes a location registration server device, acquires a node device address in the destination terminal area from the location registration server device, and sends the address and the destination to the source node device. The terminal address can be notified.

That is, in the figure, the receiving-side node device 203 inquires from the location registration server device 301 about the node device address [ADR6] where the destination terminal 101 is located, and sends the acquired address [ADR6] and the destination terminal address to the transmission source. To the node device 202.
As a result, the source node apparatus 202 knows the address [ADR6] of the node apparatus 204 in which the destination terminal 101 is currently located.

Further, the node device as the solving means 2 for the problem 2 is a node device that constitutes a communication system together with the terminal. When the destination terminal moves in the service area, at least a storage unit provided in either the terminal or the node device. Based on the stored address, it notifies the transmission source node device of its own device address and the destination terminal address.
FIG. 4 shows an operation principle of the node device according to the present invention which constitutes a communication system together with the terminal and the location registration server device. The configuration of the communication system is the same as the configuration of the communication system in FIG.

Next, the detailed operation will be described.
In general, a terminal may perform packet communication simultaneously with a plurality of terminals. In the following description, a case where the destination terminal 101 receives packets from two transmission source terminals 103 and 104 will be described. However, the solution means 2 may have a single transmission source terminal.
Further, there are cases where the location registration server device is not required and cases where it is required. Here, the location registration server device will be described.

Before the packet addressed to the destination terminal 101 is transferred, the state is as follows.
The terminal 101 is located in the area 213 of the node device 203.
The source node devices (node devices in which the source terminal is located) 201 and 202 store the address ADR5 of the node device 203 in which the terminal 101 is located in the position information tables 221 and 222, respectively.
Step S1: The terminal 101 moves to the area 214 of the node device 204.

Step S2: The node device 204 knows that the terminal 101 has moved to its own area 214 by location registration from the terminal 101 or the like.
Step S3: The node device 204 located in the destination terminal area is a storage unit (for example, the storage unit 111, the storage unit 233, or the storage unit 321) of a device (for example, a terminal, a node device, or a location registration server device) in the communication system. Etc.) based on a predetermined address (for example, the address of the transmission source terminal 104 or the transmission source node device 104), directly or indirectly via another device [ADR6] And the destination terminal device 201 and 202 are notified of the destination terminal address.

Step S4: The source node apparatuses 201 and 202 know the address of the node apparatus 204 in which the destination terminal 101 is currently located.
As a result, the source node apparatuses 201 and 202 can directly transfer a packet addressed to the terminal 101 to the node apparatus 204 in the area where the terminal 101 is located.
In addition, in the above, the destination terminal has a storage unit that stores the address of the source node device, receives the address from the destination terminal, and sends the address of the source device to the source node device of the address. Can be notified.

That is, in FIG. 4, the storage unit 111 of the destination terminal 101 stores the addresses [ADR3] and [ADR4] of the source node devices 201 and 202 in the areas where the source terminals 103 and 104 are located.
When the destination terminal 101 moves to its own area 214, the node device 204 located in the destination terminal is notified of the address of the source node device 204 stored in the storage unit 111 from the destination terminal 101 (or Inquires and receives the destination terminal), and transmits the own device address and the destination terminal address to the node devices 201 and 202 that are the transmission source of the address.

As a result, the source node devices 201 and 202 know the address of the node device 204 in the destination terminal area, and may continue to transmit packets to the former node device 203 in which the destination terminal 101 is not in the area. Disappear.
Further, in the above, the communication system further includes a location registration server device, and the destination terminal has a storage unit that stores an address of the transmission source terminal, and the address received from the destination terminal and the own device A message including the address can be transmitted to the location registration server apparatus, and the transmission source node apparatus can be notified of the own apparatus address.

That is, in the figure, the storage unit 111 of the destination terminal 101 stores the addresses [2.1.1] and [2.2.1] of the transmission source terminals 103 and 104. The node device 204 receives the address when the destination terminal 101 moves to its own area 214.
Then, the node device 204 transmits a message including the address and the own device address [ADR6] to the location registration server device 302, and the own device address [ADR6] and the destination terminal address to the source node devices 201 and 202. Request to be notified.

The location registration server apparatus 302 notifies the source node apparatuses 201 and 202 of the destination terminal area address [ADR6] and the destination terminal address.
As a result, the source node devices 201 and 202 can know the node device address [ADR6] in the destination terminal area.
Means for the node device 204 to select the location registration server device 302 from the location registration server devices 301 and 302 will be described later.

  In addition, in the above, the communication system further includes a location registration server device, a storage unit that stores the address of the source node device, and the location registration when the destination terminal moves out of its own area. It is possible to receive the device address and the destination terminal address from the new node device that is the movement destination via the server device, and to notify the transmission source node device of the device address.

That is, in the figure, the node device 203 in the destination terminal area (former area) before moving to the destination terminal is referred to as a node apparatus in the transmission source terminal area in the storage unit 233 (hereinafter referred to as a source node apparatus). Yes) Addresses [ADR3] and [ADR4] of 201 and 202 are stored.
When the destination terminal 101 moves from its own area 213 to the area 214 of the node device 204, the newly existing node device 204 sends its own device address [ADR6] and the destination terminal address via the location registration server device 301. Transmit to the node device 203.

Therefore, the former node device 203 (at this time, the destination terminal 101 has already been moved and has not moved) has been received by the source node devices 201 and 202 of the address stored in the storage unit 233. The address [ADR6] and the destination terminal address are notified.
As a result, the source node apparatuses 201 and 202 know the address [ADR6] of the destination node apparatuses 201 and 202 of the destination terminal 101.

  Further, in the above, a storage unit that stores the address of the node device in which the destination terminal is located further includes a storage unit that stores the address of the source node device, and the destination terminal is out of its own area. When the destination node device is moved, the device address and the destination terminal address are received from the destination node device of the destination terminal, and the destination node device address can be notified to the source node device.

In other words, in the same figure, before the destination terminal moves, the node device 203 in the destination terminal area (old area) stores the addresses [ADR3] [ADR4] of the source node apparatuses 201 and 202 in the storage unit 233.
Then, when the destination terminal 101 moves from its own area 213 to the area 214 of the node device 204, the destination node device 204 determines its own device address [ADR6] based on the former node device address of the storage unit 111 and The destination terminal address is directly transmitted to the node device 203.

Therefore, the node device 203 notifies the received device address [ADR6] and the destination terminal address to the source node devices 201 and 202 of the addresses [ADR3] and [ADR4] stored in the storage unit 233.
As a result, the source node devices 201 and 202 know the address [ADR6] of the destination node device 204 of the destination terminal 101.
Further, in the above, the communication system further includes a location registration server device, a storage unit that stores the address of the node device in which the destination terminal is located, and a storage unit that stores the address of the transmission source terminal. Furthermore, when the destination terminal moves out of its own area, the destination node device address notified by the destination node device of the destination terminal based on the address stored in the storage unit of the destination terminal, and A message including the destination terminal address and the stored source terminal address is sent to the location registration server apparatus, and a notification request for the destination node apparatus address and the destination terminal address is sent to the source node apparatus. It is possible.

That is, in the figure, before moving, the destination terminal 101 stores the address of the node device in which the destination terminal is located in the storage unit 111, and the node device 203 located in the destination terminal area stores the address of the source terminal in the storage unit 233. To do.
When the destination terminal 101 moves out of the area 213 of the node device 203, the destination node device 204 moves to the former node device 203 before moving the destination terminal of the address stored in the storage unit 111 of the destination terminal 101. It notifies its own device address [ADR6] and the destination terminal address.

Former node device (destination terminal node device) 203, a message including the source terminal address stored in the storage unit 233, the received device address [ADR6] and the destination terminal address, A request is sent to the registration server apparatus 302 to notify the transmission source node apparatuses 201 and 202 of the own apparatus address [ADR6] and the destination terminal address.
As a result, the source node devices 201 and 202 know the address [ADR6] of the node device 204 in the destination terminal area.

  In the above, the communication system further includes a location registration server device, the location registration server device further includes a storage unit that stores the address of the source node device, and the destination terminal moves to its own area. A message including the own device address and the destination terminal address is transmitted to the location registration server device, and the own device address and the destination terminal address are notified to the source node device. It is possible to make a request to the location registration server device.

That is, the storage unit 321 of the location registration server device 301 stores the source node device addresses [ADR3] and [ADR4].
When the destination terminal 101 moves to its own area 214, the node device 204 located in the destination terminal area sends a message (eg, location registration request) including its own device address [ADR6] and the destination terminal address to the location registration server. This message is sent to the device 301, and this message is requested to notify the source node device 201, 202 of the own device address [ADR6] and the destination terminal address.

Based on the address stored in the storage unit 321, the location registration server apparatus 301 notifies the transmission source node apparatuses 201 and 202 of the own apparatus address [ADR6] and the destination terminal address.
As a result, the source node devices 201 and 202 know the node device address [ADR6] of the destination terminal area, and thereafter directly transfer the packet addressed to the destination terminal 101 to the area node device 204. become.

  In the above, the communication system further includes a location registration server device, the location registration server device has a storage unit that stores the address of the source node device, and the destination terminal moves to its own area. Then, the location registration server device can be inquired of the source node device address, and the source node device can be directly notified of the own device address and the destination terminal address.

That is, in the same figure, the location registration server apparatus 301 stores the addresses [ADR3] [ADR4] of the source node apparatuses 201 and 202 in the storage unit 321.
When the destination terminal 101 moves to its own area 214, the node device 204 that is in the destination terminal area is the node device (the transmission source terminal) in which the source terminals 103 and 104 that are transmitting packets to the destination terminal are located. Query the node device address.

The location registration server device 301 searches the storage unit 321 and returns the source node device address [ADR3] [ADR4]. The node device 204 directly transmits its own device address [ADR6] and the destination terminal address to the source node devices 201 and 202.
As a result, the source node devices 201 and 202 know the node device address [ADR6] where the destination terminal 101 is located.

  Further, in the above, the communication system further includes a location registration server device, the location registration server device further includes a storage unit that stores an address of a transmission source terminal corresponding to the destination terminal, When moving to its own area, a message including its own device address and the destination terminal address is transmitted to the location registration server device, and the own device address and the destination terminal address are sent to the source node device. Requests to be notified can be made.

That is, in the figure, the storage unit 321 of the location registration server device 301 stores the addresses of the transmission source terminals 103 and 104.
When the destination terminal 101 moves to its own area 214, the node device 204 located in the destination terminal area sends a message (eg, location registration request) including its own device address [ADR6] and the destination terminal address to the location registration server. This message is sent to the device 301, and this message is requested to notify the source node device 201, 202 of the own device address [ADR6] and the destination terminal address.

Based on the address stored in the storage unit 321, the location registration server device 301 notifies the source node device 201, 202 of the destination device location node device address [ADR6] and the destination terminal address.
As a result, the source node devices 201 and 202 know the node device address [ADR6] of the destination terminal area, and thereafter directly transfer the packet addressed to the destination terminal 101 to the area node device 204. become.

  Further, in the above, the communication system further includes a location registration server device, the location registration server device further includes a storage unit that stores an address of a transmission source terminal corresponding to the destination terminal, and the destination terminal itself When moving to the area, the address of the source terminal is received from the location registration server device, and the address of the source node device in which the source terminal of this address is located is received from the location registration server device Thus, the own device address and the destination terminal address can be directly transmitted to the source node device.

That is, in the figure, the storage unit 321 of the location registration server apparatus 301 stores the addresses of the transmission source terminals 103 and 104 corresponding to the destination terminal 101.
The node device 204 inquires of the location registration server device 301 about the addresses of the transmission source terminals 103 and 104 when the destination terminal 101 has moved to its own area 214.
The location registration server device 301 returns the address stored in the storage unit 321 to the node device 204.

The node device 204 inquires of the location registration server device 302 about the address of the transmission source node device in which the transmission source terminal of the received address is located. The location registration server device 302 returns the source node device addresses [ADR3] and [ADR4] to the node device 204.
Based on these addresses [ADR3] and [ADR4], the node device 204 directly transmits its own device address [ADR6] and the destination terminal address to the source node devices 201 and 202.

As a result, the source node devices 201 and 202 know the node device address [ADR6] of the destination terminal area, and thereafter directly transfer the packet addressed to the destination terminal 101 to the area node device 204. become.
In addition, in the above, when the location registration server device stores the location of the transmission source terminal stored in the storage unit in the location registration table of the device itself, another location registration in which the transmission source terminal is registered A request can be made to the server device for the node device address of the destination terminal and the destination terminal address notification request to the source node device.

In other words, in the same figure, the location registration server device 301, when the location registration of the transmission source terminals 103 and 104 of the address stored in the storage unit 321 is not made in the location registration table 311 of its own device, Is requested to notify another location registration server device 302 in which the destination terminal is located and the destination device address [ADR6] and the destination terminal address.
The location registration server device 302 notifies the node device 201 and 202 in the source terminal area of the node device address [ADR6] of the destination terminal area and the destination terminal address.

As a result, the node devices 201 and 202 know the node device address [ADR6] in the destination terminal area, and thereafter directly transfer the packet addressed to the destination terminal 101 to the area node device 204.
Further, in the above, the storage unit of the terminal can be included in an adapter connected to the terminal.

That is, the storage unit can be mounted on an adapter connected to the terminal. According to this, when the storage unit is not necessary, it can be disconnected from the terminal, and the price and weight of the terminal can be reduced.
In addition, in the above, the packet transmitted / received between the devices is at least the necessity of transferring / unnecessary forwarding of the own packet, the designation of the forwarding destination, the necessity / unnecessity of the response message, It is possible to specify either one of the response destinations.

That is, in a communication system, a packet transmitted / received between a node device and a location registration server device (when the location registration server device is included in the communication system) designates at least one of the following for a destination device: It is possible.
1) Specify whether to forward the received packet, 2) In case of forwarding in 1) above, specify the destination device, 3) Specify whether a response message is required, 4) In 3) above If necessary, designation of the transmission destination of the response message In the above, the message transmitted / received between the devices is at least designated as necessity / unnecessity of the response message to the transmission destination device, and the response destination You can specify.

That is, in a communication system, messages transmitted and received between a node device and a location registration server device (when the location registration server device is included in the communication system) are: 2) If necessary, it is possible to specify the destination of the response message.
In the above, the communication system may have a plurality of location registration server devices, and may have a server search table in which the destination terminal is associated with the location registration server device address where the destination terminal is registered.

As a result, even when the communication system includes a plurality of location registration server devices, the node device is a location registration server device that should register the location of the located terminal, and the node where the transmission source or destination terminal is located It becomes possible to know the location registration server device that inquires about the device address.
In the above, it is possible to configure the communication system by connecting the devices by a router.

In the above, it is possible to configure the communication system by connecting the devices by ATM-SW.
Furthermore, in the above, at least one of the terminals may be a fixed terminal, and at least one of the terminals may be a fixed communication network node device.
That is, at least one of the node devices may be a fixed communication network node device to which a fixed terminal is connected.

As described above, according to the node device according to the present invention, it is possible to prevent deterioration in communication quality due to packet loss that occurs when the destination terminal moves to the area of another node device.
In addition, since the stored node location information is not updated, the transmission source node device does not continue to transmit the packet to the former node device in which the destination terminal was located. It becomes possible to transfer correctly.

Embodiments (1) to (24) of a communication system configured with node devices according to the present invention will be described below. In the embodiments (1) to (23), the node device constitutes a sub-communication system together with the terminal and the location registration server device, and these sub-communication systems are connected by a router and connected to a general IP (Internet)
Protocol) A communication system (router network) is configured.

In the embodiment (24), a configuration example of a communication system applied to an ATM network is shown. In addition,
In each sub-communication system, only necessary devices are illustrated, and other devices are omitted.
Normally, when the terminal moves to the area of the node device, location registration is performed in the location registration server device, but this normal location registration is not shown.
However, although this normal location registration may be illustrated in some embodiments, the location registration in this case is indicated by a dashed arrow.

Note that either a mobile network (wireless or the like) or a fixed network (wired or the like) can be connected to the node devices of the embodiments (1) to (24) of the present invention.
To move a terminal, change the connection of a fixed terminal (station device) connected to the fixed network node device to another fixed network node device, or move from the area of the mobile network node device to the area of another mobile network node device. It is to be.

Further, for example, a terminal having both functions of connecting to a mobile network and a fixed network can move between the mobile network node device and the fixed network node device.
In the embodiments (1) to (24), these movements are simply described as “the destination terminal moves from the area of the node device to the area of another node device”.
(i) Embodiment of Solution 1 for Problem 1 (Embodiment (1) in FIG. 5 to Embodiment (3) in FIG. 7 and FIG. 9)
Example (4))
These embodiments solve the problem 1 (eliminating packet loss caused by the destination terminal moving to an area of another node device) solving means 1 (location information of the destination terminal of the node device or location registration server device). To transfer the packet directly to the node device in the destination terminal area or directly via another device.

FIG. 5 shows an embodiment (1) of the node device according to the present invention constituting the communication system.
In the configuration of this communication system, a general IP (Internet Protocol) network (router network) is applied as a communication system between the location registration server devices 301 and 302 and the node devices 201 to 204.
That is, the location registration server devices 301 and 302 and the node devices 201 to 204 are connected by the routers 501 to 506, respectively, to constitute an IP network.

The location registration server devices 301 and 302 and the node devices 201 to 204 are assigned IP addresses [133.1.1] to [133.1.6], respectively.
Hereinafter, the operation of this embodiment will be described in the order of processing steps.
The state of the communication system before packet transfer is as follows.
The terminal 101 is located in the area 213 of the node device 203.

The source node device 202 stores the address [133.1.5] of the node device 203 in the area where the terminal 101 is located in the position information table 222.
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network via the node device 204.

Step S3: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.
Step S5: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].

Step S6: The user packet 71 addressed to the terminal 101 arrives at the node device 202.
Step S7: The node device 202 searches the location information table 222 to obtain the address [133.1.5] of the node device 203 in the area where the terminal 101 is located.
Step S8: The node device 202 adds the address [133.1.5] of the node device 203 to the received packet 71 addressed to the terminal 101 and transfers it as the inter-node packet 81.

Step S9: The node device 203 that has received the packet 81 searches the server search table 40 when the destination terminal 101 is not located, and searches for the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101. Get the address [133.1.1].
Step S10: The node device 203 rewrites the destination address of the packet 81 to [133.1.1] and transfers it to the location registration server device 301.

Step S11: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located.
Step S12: The location registration server apparatus 301 transfers the packet 83 in which the destination address of the received packet 82 is rewritten to [133.1.6] to the node apparatus 204.
As a result, even when the terminal 101 moves from the area 213 of the node device 203 to the area 214 of the node device 204 during communication, the packet 71 passes through the node device 203, the location registration server device 301, and the node device 204. And transferred to the destination terminal 101.

In steps S3 and S9, the node devices 204 and 203 search the server search table 40 and acquire the address of the location registration server device 301 corresponding to the address of the terminal 101. However, the communication system has one location. When only the registration server device is provided, the node device 204 does not need to include the server search table 40.
That is, when location registration information is distributed and registered in a plurality of location registration server devices, the node device and the location registration server device in the embodiment (22) described later need to include the server search table 40.

  Further, in this embodiment, before the address of the node device 204 located in the terminal 101 in the location registration table 311 is updated to [133.1.6] in step S5, the node is sent to the location registration server device 301 by steps S6 to S10. When the inter-packet 82 is transferred, the location registration server device 301 loops between the node device 203 and the location registration server device 301 in order to transfer the inter-node packet to the pre-update address [133.1.5]. May occur.

The countermeasures include the following.
(1) Use the Time To Live field included in the header of the IP packet to discard the packet when the number of routers passing through exceeds the set value.
(2) The location registration server device 301 compares the source address of the inter-node packet 82 with the node device address of the destination terminal in the user packet 71 registered in the location registration table 311.
If it is the same address, it is judged that a loop will occur and discarded, or if the number of routers that pass through using the Time ToLive field is the same as (1) or less, the destination terminal will register the location. Wait until it is set, and discard it if it exceeds the set value.

FIG. 6 shows an embodiment (2) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is the same as that of the embodiment (1) of FIG. 5, but in this embodiment (2), in the embodiment (1), packets are received from the receiving side node device 203 to the location registration server device 301. Is transmitted via the transmission source node device 202.
Hereinafter, steps after the state of Step S8 in which the packet 81 is transmitted from the node device 202 to the node device 203 in the embodiment (1) will be described.

Step S9: When the destination terminal 101 is not in the area 213, the node device 203 uses the destination address of the received inter-node packet 81 (see FIG. 5) as [133.1.4] of the source node device 202. ], The node-to-node packet 82 rewritten to [] is returned to the node device 202.
Step S10: The node device 202 searches the location information table 222 for the address of the node device located in the terminal 101 and obtains [133.1.5]. Since this address matches the source address of the packet 82, that is, its own device address [133.1.5], it is determined that the terminal 101 is not located in the node device 203.

Step S11: Therefore, the node device 202 searches the address of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 from the server search table 40, and obtains [133.1.1].
Step S12: The node device 202 transfers the inter-node packet 83 in which the destination address of the received packet 82 is rewritten to [133.1.1] to the location registration server device 301.
Thereafter, the operations of steps S11 and S12 of the embodiment (1) shown in FIG. 5 are executed.

As a result, the packet 71 transmitted from the terminal 104 is not discarded and is transferred to the destination node device 204 of the destination terminal via the node device 202, the node device 203, the node device 202, and the location registration server device 301. It will be transferred in packets between nodes.
As a modification of this embodiment (2), after step S11, the node device 202 inquires the location registration server device 301 about the node device address of the destination terminal, and directly transfers the packet 82 to the node device 204. May be.

FIG. 7 shows an embodiment (3) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is the same as that of the embodiment (2) in FIG. 6, but in this embodiment (3), in the embodiment (2), the receiving side node device 203 receives the packet 81 (FIG. 5) is returned to the node device 202 of the transmission source, instead of directly returning to the node device 202, it is performed via the location registration server device corresponding to the transmission source terminal.

Hereinafter, steps after the state of Step S8 in which the packet 81 is transmitted from the node device 202 to the node device 203 in the embodiment (1) will be described.
Step S9: When the destination terminal 101 is not located, the node device 203 searches the server search table 40 and searches for the address [133.1. Address of the location registration server device 302 corresponding to the address [2.2.1] of the transmission source terminal 104. 2] is obtained.

Step S10: The node device 203 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.2] to the location registration server device 302.
At this time, means for displaying that the packet 82 is a reply packet will be described later with reference to FIG.
Step S11: The location registration server device 302 searches the location registration table 312 to obtain the address [133.1.4] of the node device 202 in the area where the terminal 104 is located.

Step S12: The location registration server apparatus 302 transfers the inter-node packet 83 in which the destination address of the received packet 82 is rewritten to [133.1.4] to the node apparatus 202.
Thereafter, the operations of steps S10 to S12 of the embodiment (2) in FIG. 6 and steps S11 and S12 of the embodiment (1) in FIG. 5 are executed.
As a result, the packet 71 is sent to the destination terminal 101 via the node devices 202 and 203, the server 302, the node device 202, the server 301, and the node device 204.

FIG. 8 shows an embodiment of the inter-node packet 82 in step S10 of the embodiment (3) shown in FIG. The packet 82 is returned as a packet 83 from the receiving side node device 203 to the transmission source node device 202 via the location registration server device 302 corresponding to the transmission source terminal 104.
The packet 82 includes a destination address field 91, a transmission source address field 92, and a message packet field 90.

In the fields 91 and 92, the address [133.1.2] of the destination location registration server apparatus 302 of the packet 82 and the address [133.1.5] of the source node apparatus 203 are set, respectively.
The field 90 includes a message destination address field 93, a message transmission source address field 94, a message information field 95, and a user packet field 71.

In the fields 93 and 94, the address [133.1.2] of the location registration server apparatus 302 that is the destination of the message and the address [133.1.5] of the node apparatus 203 that is the source of the message are set, respectively.
The field 95 includes “the presence / absence of a user packet 71”, “message information field length”, and “message type”.

In the field 95 of the packet 82 in step S10, “presence / absence of user packet 71” = “present” and “message type” = “reply to the source node device” are displayed. 71 is inserted.
The location registration server apparatus 302 that has received the packet 82 decodes the content of the message information field 95 and recognizes that the type of the message packet is “reply to the source node apparatus”.

Therefore, the location registration server apparatus 302 searches the location registration table 312 in step S11 of the embodiment (3) in FIG. 7, refers to the source address 97 of the user packet 71, and has the terminal with the address [2.2.1]. The address [133.1.4] of the node device 202 in which 104 is located is obtained.
FIG. 9 shows an embodiment (4) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is the same as that of the embodiment (1) in FIG.

This embodiment (4) shows the operation following step S8 of the embodiment (1) shown in FIG. That is, after the receiving-side node device 203 receives the inter-node packet 81 (see the figure), the node device address of the terminal 101 is acquired from the location registration server device 301 and transferred to the node device 204 of the destination terminal location. The case of transferring a packet is shown.
The detailed operation after step S8 in the embodiment (1) will be described below.

Step S9: When the destination terminal 101 is not located, the node device 203 searches the server search table 40 and the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 Get.
Step S10: The node device 203 transmits to the location registration server device 301 a message inquiring about the node device address where the terminal 101 is located.

Steps S11 and S12: The location registration server device 301 refers to the location registration table 311 to search for the address [133.1.6] of the node device 204 located in the terminal 101 and notifies this to the node device 203.
Step S13: The node device 203 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.6] to the node device 204.
As a result, the node device 203 can transfer the received packet 81 to the node device 204 where the terminal 101 is located even when the destination terminal 101 is not located within the area.

(ii) Embodiment of Solution 2 for Problem 1 (Embodiment (5) in FIG. 10 to Embodiment (11) in FIG. 16)
These embodiments solve Problem 1 (eliminate packet loss caused by moving the destination terminal to another node device area) Solution 2 (when the destination terminal moves to its own area, (Directly or indirectly acquiring the address of the former node device in which the destination terminal was located and notifying the former node device directly or via another device) Solve based on.

FIG. 10 shows an embodiment (5) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is different from the embodiment (1) of FIG. 5 only in that the terminal 101 is provided with a storage unit (cache) 111 that stores the address of the node device 203 located before the movement. Yes.
Note that the node device 203 in FIG. 10 shows a position information table 223 which is not shown in FIG.

Further, the terminal 101 may not include the cache 111 but may include the cache 111 in the adapter and connect the adapter to the terminal 101 as necessary.
In this embodiment (5), first of all, the destination terminal 101 stores the old node device address in the cache 111, and whenever it moves to the new node device, the new node Notify device address.

The detailed operation of the embodiment (5) will be described below.
In the state before the operation in which the transmission source terminal 104 transmits the packet 71, the terminal 101 is in the area 213 of the node device 203, and the transmission source node device 202 is the address of the node device 203 in the area of the terminal 101. [133.1.5] is stored in the position information table 222.
Step S1: The terminal 101 moves to the area 214 of the node device 204.

Step S2: The terminal 101 stores the address [133.1.5] of the former node device 203 in the cache 111.
Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the former node device 203 is notified to the node device 204.
Step S4: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.

Step S5: The node device 204 transmits the location registration information to the location registration server device 301.
Step S6: The node device 204 notifies the node device 203 of its own device address [133.1.6] and the destination terminal address.
Step S7: The location registration server device 301 updates the node device address of the terminal 101 (address [1.1.1]) in the location registration table 311 to [133.1.6].

Step S8: The node device 203 adds the address [1.1.1] of the terminal 101 and the address [133.1.6] of the serving node device 204 to the position information table 223 “for inter-node packet transfer”.
Step S9: The terminal 104 transmits a user packet 71 addressed to the terminal 101.
Step S10: The node device 202 retrieves the address [133.1.5] of the node device 203 in the area where the destination terminal 101 of the received packet 71 is located from the position information table 222 “for user packet transfer”.

Step S11: The node device 202 adds the address [133.1.5] of the node device 203 to the received packet 71 addressed to the terminal 101 and transfers it as the inter-node packet 81.
Step S12: Since the destination device 101 does not exist in its own area 213, the node device 203 refers to the location information table 223 and determines from the address [1.1.1] of the destination terminal 101 included in the packet 81 The address [133.1.6] of the node device 204 that is in the area is searched.

Step S13: The node device 203 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.6] to the node device 204.
Thereafter, the packet 71 included in the packet 82 is delivered to the destination terminal 101 via the node device 204.
As described above, the location information table 223 indicates that when the receiving node device receives the inter-node packet, the destination node device address is referred to when the destination terminal is not located in the own device. It is a table to know.

On the other hand, the position information table 222 is a conventional table for referring to the destination node device address of the user packet received from the transmission source terminal by the transmission source node device.
When the table 223 indicates a destination terminal address and a node device address where the destination terminal is located, a position information table (not shown) for user packet transfer included in the node device 203
It is also possible to use it together. However, the search time will be delayed if they are also used.

In the following embodiments, description will be made assuming that the position information tables for inter-node packets and user packets are shared.
FIG. 11 shows an embodiment (6) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is such that a router 507 and a node device 205 are further connected via the router 507 to the communication system of the embodiment (5) in FIG. The node device 205 is assigned an address [133.1.7] and has an area 215.

In the present embodiment (6), firstly speaking, when the destination terminal 101 stores the address [133.1.5] of the communication start node device 203 in the cache 111 and moves to the new node device, the communication start node device The new node device address is notified to 203.
Hereinafter, a detailed operation of the packet transfer of the embodiment (6) will be described.
As a state before the packet transfer operation, the terminal 101 is in the area 213 of the node device 203 that has started communication, and the source node device 202 has the address [133.1.5 ] Is stored in the position information table 222.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the address [133.1.5] of the communication start node device 203 in the cache 111.
Is remembered.
Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the communication start node device 203 is notified.

Step S4: The node device 204 notifies the communication start node device 203 of its own device address [133.1.6] and the destination terminal address.
Step S5: The node device 203 adds the terminal 101 and the address [133.1.6] of the serving node device to the location information table 223.
Step S6: The terminal 101 moves to the area 215 of the node device 205.

Step S7: The terminal 101 stores the address [133.1.5] of the communication start node device 203 in the cache 111.
Holding.
Step S8: The terminal 101 notifies the address [133.1.5] of the communication start node device 203 to the network.
Step S9: The node device 205 notifies the communication start node device 203 of its own device address [133.1.7] and the destination terminal address.

Step S10: The node device 203 updates the node device address of the terminal 101 in the position information table 223 to [133.1.7].
Steps S11 to S13: The user packet 71 addressed to the terminal 101 from the terminal 104 is included in the inter-node packet 81 and transferred to the node device 203.
Step S14: The node device 203 searches the location information table 223 to obtain the address [133.1.7] of the node device 205 in the area where the terminal 101 is located.

Step S15: The node device 203 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.7] to the node device 205.
As a result, the node device 203 can transfer, for example, a packet addressed to the terminal 101 that has moved outside its own area during communication to the node device 205 in the area where the terminal 101 is located. Similarly, even when the terminal 101 sequentially moves in the area where the terminal 101 is located, it can be similarly transferred to the node device in which the terminal 101 is currently located.

FIG. 12 shows an embodiment (7) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is the same as that of the embodiment (6) shown in FIG. 11, but the position information table 224 and the server search table 40 not shown in the figure are shown.
First of all, in the embodiment (6), every time the destination terminal 101 moves to the new node device, only the communication start node device 203 is notified of the new node device address and the destination terminal address. In the embodiment (9), the cache 111 of the destination terminal 101 stores the addresses of all the formerly visited node devices including the communication start node device 203 that has moved so far, and moves to the newly visited node device each time. The new existing node device address and the destination terminal address are notified to all former existing node devices including the communication start node device.

The detailed operation of the embodiment (7) will be described below.
The state before the packet transfer operation is the same as the state before the operation of the embodiment (6).
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the address [133.1.5] of the communication start node device 203 in the cache 111.
Is remembered.

Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the communication start node device 203 is notified to the network.
Step S4: The node device 204 searches the server search table 40 for the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Steps S5 and S6: The node device 204 transmits location registration information to the location registration server device 301,
The node device 203 is notified of its own device address [133.1.6] and the destination terminal address.

Step S7: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Step S8: The node device 203 adds the address [133.1.6] of the terminal 101 and its serving node device to the location information table 223.
Step S9: The terminal 101 moves to the area 215 of the node device 205.

Step S10: The terminal 101 stores the address [133.1.5] of the communication start node device 203 and the address [133.1.6] of the former node device 204 in the cache 111.
Step S11: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the communication start node device 203 and the address [133.1.6] of the former node device 204 are notified to the network.

Steps S12 and S13: The node device 205 searches the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 from the server search table 40, and sends the location to the location registration server device 301. Send registration information.
Step S14: The node device 205 notifies the node devices 203 and 204 of the address [133.1.7] of the node device 205 and the destination terminal address.

Step S15: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.7].
Step S16: The node device 203 updates the node device address where the terminal 101 is located in the location information table 223 to [133.1.7].
Step S17: The node device 204 adds the address [133.1.7] of the terminal 101 and its serving node device to the location information table 224.

As a result, the node devices 203 and 204 know the address of the node device in which the destination terminal 101 is currently located.
Thereafter, when the node devices 203 and 204 receive the inter-node packet 81 addressed to the terminal 101, the node devices 203 and 204 perform the same operations as steps S11 to S13 in the embodiment (5) shown in FIG. Transfer to the node device 205.

FIG. 13 shows an embodiment (8) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is different from the configuration of the embodiment (7) of FIG. 12 in that the node devices 204 and 205 are respectively provided with storage units 234 and 235 (may be collectively referred to by reference numeral 23). That is.
Another difference is that the storage unit 111 of the destination terminal 101 stores only the address of the node device that was in the area immediately before.

The storage units 234 and 235 of the node devices 204 and 205 store the addresses of the node devices that are located immediately before the destination terminal 101 moves in the area.
In this embodiment (8), first, in brief, the storage unit 111 stores the address of the node device that was in the area immediately before, and the storage unit 23 of the new existing node device stores this address.
Then, every time the destination terminal 101 moves to the area of the new area node device while the communication is continuing, the new area node device notifies its previous device address and the destination terminal address to the previous old area node device. Then, the old node device refers to the storage unit 23 of its own device, and notifies the previous old node device of the previous node of the address of the new node device and the destination terminal address.

By repeating this, the node device address of the newly located area is notified to all the node devices where the destination terminal 101 is located.
The detailed operation of the embodiment (8) will be described below. The state before the operation is the same as that in the embodiment (7).
Step S1: The terminal 101 moves to the area 214 of the node device 204.

Step S2: The terminal 101 stores the address [133.1.5] of the former node device 203 in the cache 111.
Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the communication start node device 203 is notified to the network.
Step S4: The terminal 101 updates the cache 111 to the address [133.1.6] of the visited node device 204.

Step S5: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S6: The node device 204 transmits the location registration information to the location registration server device 301.
Step S7: The node device 204 stores the address [1.1.1] of the terminal 101 and the address [133.1.5] of the former node device 203 in the cache 234.

Step S8: The node device 204 notifies the node device 203 of its own device address [133.1.6] and the destination terminal address.
Step S9: The location registration server device 301 updates the visited node device address of the terminal 101 in the location registration table 311 to [133.1.6].
Step S10: The node device 203 adds the address [1.1.1] of the terminal 101 and the corresponding visited node device address [133.1.6] to the location information table 223.

Step S11: The terminal 101 moves to the area 215 of the node device 205.
Step S12: The terminal 101 stores the address [133.1.6] of the former node device 204 in the cache 111.
Step S13: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.6] of the former node device 204 is notified to the network.

Step S14: The terminal 101 updates the address of the cache 111 to [133.1.7].
Step S15: The node device 205 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S16: The node device 205 transmits the location registration information to the location registration server device 301.
Step S17: The node device 205 stores the address [1.1.1] of the terminal 101 and the corresponding former node device address [133.1.6] in the cache 235.

Step S18: The node device 205 notifies the node device 204 of its own device address [133.1.7] and the destination terminal address.
Step S19: The location registration server device 301 updates the visited node device address corresponding to the terminal 101 in the location registration table 311 to [133.1.7].
Step S20: The node device 204 adds the address [1.1.1] of the terminal 101 and the corresponding visited node device address [133.1.7] to the location information table 224.

Step S21: The node device 204 searches the cache 234 for the address [133.1.5] of the former node device of the terminal 101.
Step S22: The node device 204 notifies the node device 203 of the address [133.1.7] of the node device 205 and the destination terminal address.
Step S23: The node device 203 updates the visited node device address corresponding to the terminal 101 in the location information table 223 to [133.1.7].

As a result, the node devices 203 and 204 store the address [133.1.7] of the node device 205 where the destination terminal is currently located in the position information tables 224 and 223, respectively.
Thereafter, when the node devices 203 and 204 receive the inter-node packet 81 addressed to the terminal 101, the operations of steps S13 to S15 in the embodiment (6) of FIG. 11 are executed. The node device 205 is directly transferred.

FIG. 14 shows an embodiment (9) of the node device according to the present invention which constitutes the communication system.
The configuration of this communication system is the same as that of the embodiment (5) in FIG. 10 except that the destination terminal 101 does not have the cache 111.
Generally speaking, the operation of the present embodiment (9) is different from the embodiment (5) in which the cache 111 stores the former node device address, so that the destination terminal 101 registered in the location registration server device 301 is the same. The old node device address is acquired from the location registration information of the node, and the old node device address and the destination terminal address are notified to the old node device.

The detailed operation of the embodiment (9) will be described below.
The state of the communication system before the terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network.

Step S3: The node device 204 searches the server search table 40 for the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.
Step S5: The location registration server device 301 refers to the location registration table 311 and searches for the address [133.1.5] of the node device in which the terminal 101 is located.

Step S6: The location registration server device 301 notifies the node device 203 of the address [133.1.6] of the node device 204 in which the destination terminal 101 is located and the destination terminal address.
Step S7: The location registration server device 301 updates the address of the node device in the location of the terminal 101 in the location registration table 311 to the location registered address [133.1.6].
Step S8: The node device 203 adds the address [1.1.1] of the terminal 101 and the address [133.1.6] of the visited node device to the position information table 223.

Thereafter, the operations of steps S9 to S13 of the embodiment (5) shown in FIG. 10 are executed.
As a modification of the embodiment (9), in the above steps S4 to S7, the node device 204 may transmit its own device address and the destination terminal address as follows.
Before the node device 204 registers the location of the destination terminal 101, the node device 204 transmits a message about the location of the destination node device in the destination terminal 101 to the location registration server device 301, and the address [ Obtain 133.1.5].

Based on this address, the node device 204 directly transmits its own device address [133.1.6] and the destination terminal address to the former node device 203.
FIG. 15 shows an embodiment (10) of the node device according to the present invention which constitutes the communication system. The configuration of this communication system is the same as that of the embodiment (6) shown in FIG. 11, except that the terminal 101 does not hold the storage unit 111.

First of all, in the embodiment (6), the communication start node device 203 stored in the destination terminal 101 is used.
Based on the address [133.1.5], the node device 203 is notified of the new-zone node device address every time it moves to the new-zone node device.
On the other hand, in the present embodiment (10), the location registration server device 301 stores the address [133.1.5] of the communication start node device 203, and the communication start node device every time the destination terminal 101 moves to the new node device. Is notified of the new node device address and the destination terminal address.

The detailed operation of the embodiment (10) will be described below.
The state of the communication system before the terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203 that has started communication, and the source node device 202 stores the address [133.1.5] of the node device 203 located in the terminal 101 in the position information table 222. I remember it.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network. At this time, it is notified that communication is in progress.
Steps S3 and S4: The node device 204 searches the server registration table 40 for the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101, and sends the location to the location registration server device 301. Send registration information. At this time, it is notified that communication is in progress.

Step S5: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.5] of the node device in the area where the terminal 101 is located.
Step S6: The location registration server device 301 notifies the node device 203 of the address [133.1.6] of the node device 204 and the destination terminal address. At this time, the location registration table is not updated because communication is in progress.

Step S7: The node device 203 adds the address [1.1.1] of the terminal 101 and the address [133.1.6] of the visited node device to the position information table 223.
Step S8: The terminal 101 moves to the area 215 of the node device 205.
Steps S9 to S13: The same operations as in steps S2 to S6 are performed.
Step S14: The node device 203 updates the node device address of the terminal 101 in the location information table 223 to [133.1.7].

Thereafter, operations similar to those in steps S11 to S15 in the embodiment (6) of FIG. 11 are performed, and the node device 203 directly transfers the packet 81 as the packet 82 to the node device 205 in the area where the destination terminal 101 is located. become.
FIG. 16 shows an embodiment (11) of the node device according to the present invention which constitutes the communication system. In the configuration of this communication system, the location registration server device 301 includes a storage unit (cache) 321 corresponding to each terminal, and the addresses of all the former node devices are stored in the cache 321 in the embodiment of FIG. It is different from (10).

Further, FIG. 16 shows a position information table 224 of the node device 204 that is not shown in FIG.
First, in summary, in the embodiment (10), the location registration server device 301 notifies the communication start node device 203 of the node device address of the destination terminal and the destination terminal address while the communication is continuing. In the example (11), each time the location registration server device 301 moves to the newly located node device, the location registration server device 301 sends the newly located node device address and the destination to all the node devices where the destination terminal is located. Notify the terminal address.

The detailed operation of the embodiment (11) will be described below. The state of the communication system before the terminal 101 moves is the same as in the embodiment (10).
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network. At this time, it is notified that communication is in progress.

Step S3: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301. At this time, it is notified that communication is in progress.
Steps S5 and S6: The location registration server device 301 updates the node device address of the location of the terminal 101 in the location registration table 311 to [133.1.6] and the address [133.1.5] of the former location of the node device 203. Is stored in the cache 321 corresponding to the terminal 101.

Step S7: The location registration server device 301 notifies the node device 203 of the address [133.1.6] of the node device 204 and the destination terminal address.
Step S8: The node device 203 adds the address [1.1.1] of the terminal 101 and the address [133.1.6] of the visited node device to the position information table 223.
Step S9: The terminal 101 moves to the area 215 of the node device 205.

Step S10: The terminal 101 performs location registration with respect to the network. At this time, it is notified that communication is in progress.
Step S11: The node device 205 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S12: The node device 205 transmits the location registration information to the location registration server device 301. At this time, it is notified that communication is in progress.

Step S13: The location registration server device 301 updates the visited node device address corresponding to the address [1.1.1] of the terminal 101 in the location registration table 311 to [133.1.7].
Step S14: The location registration server device 301 adds the address [133.1.6] of the former node device 204 to the cache 321 corresponding to the terminal 101.
Step S15: The location registration server device 301 notifies the node device 203 and the node device 204 of the address [133.1.7] of the node device 205 and the destination terminal address based on the cache 321.

Steps S16 and S17: The node devices 203 and 204 update and add the node device address of the terminal 101 in the location information tables 223 and 224 to [133.1.7], respectively.
Thereafter, when the node device 203 receives the inter-node packet 81 addressed to the terminal 101, the same operation as in steps S11 to S15 in the embodiment (6) of FIG. Transfer directly to the node device 205.

Similarly, when the node device 204 receives the packet 81 addressed to the terminal 101, the node device 204 directly transfers the packet 81 to the node device 205.
As a modification of the embodiment (11), in the above steps S4 to S7, the node device 204 sends its own device address [133.1.6] and the destination terminal address via the location registration server device 301. Although it transmitted to the area node device 203, the own device address and the destination terminal address may be transmitted as follows.

That is, the node device 204 transmits a visited node device address inquiry message of the destination terminal 101 to the location registration server device 301. The location registration server device 301 returns the address [133.1.5] stored in the cache 321 to the node device 204.
Then, based on this address, the node device 204 directly transmits its own device address and the destination terminal address to the former node device 203.

Similarly, instead of steps S12 to S15, the newly located node device 205 sends an inquiry message to the location registration server device 301 and sets the addresses [133.1.5] and [133.1.6] of the node devices 203 and 204. Acquire and transmit the own device address [133.1.7] and the destination terminal address to the node devices 203 and 204.
(iii) Example of Solution 1 for Problem 2 (Example (12) in FIG. 17 to Example (15) in FIG. 20)
In these embodiments, since the location information stored in the source node device is not updated even though the destination terminal has moved, the destination node device is in the service area. Means 1 for solving the problem of continuing to transmit packets to the former node device (when the packet arrives at the receiving node device, the location information of the destination terminal stored in the source node device is updated) ).

FIG. 17 shows an embodiment (12) of the node device according to the present invention which composes the communication system. In the configuration of this communication system, the node device 203 includes a storage unit (cache) 233 instead of the cache 111 of the destination terminal 101 of the embodiment (5) shown in FIG. The storage unit 233 can also be used as a position information table.
The cache 233 stores the address [1.1.1] of the destination terminal 101 and the address [133.1.6] of the node device 204 in the destination terminal 101 area in association with each other.

The operation until the cache 233 stores the address of the node device in the destination terminal area includes, for example, the embodiment (5) in FIG. 10 to the embodiment (11) in FIG.
First, in summary, in the present embodiment (12), the former node device 203 is configured such that the address [133.1.6] of the node device 204 in the destination terminal 101 and the destination node address are the source node device. Notify 202.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
In the state before the transmission source terminal 104 sends the packet 71, the address [133.1.6] is stored in the cache 233, and the terminal 101 moves from the area 213 of the node device 203 to the area 214 of the node device 204, and transmits. The original node device 202 stores the address [133.1.5] of the former node device 203 of the terminal 101 in the position information table 222.

Steps S1 to S3: The node device 202 transfers the inter-node packet 81 with the address [133.1.5] of the node device 203 added to the received packet 71 addressed to the terminal 101.
Steps S4 and S5: The node device 203 searches the cache 233 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located, and notifies the node device 202 of this address and the destination terminal address.

Step S6: The node device 202 updates the node device address where the terminal 101 is located in the location information table 222 to [133.1.6].
As a result, the node device 202 can directly transfer the packet 71 addressed to the terminal 101 to the node device 204 in the area where the terminal 101 is located.
FIG. 18 shows an embodiment (13) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as that of the embodiment (1) shown in FIG.

In this embodiment (13), first of all, the former node device 203 transfers the received inter-node packet 81 to the location registration server device 301 and transmits it to the location registration server device 301. It requests the original node device 202 to notify the address [133.1.6] of the node device 204 in the destination terminal area and the destination terminal address.
Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.

In FIG. 18, the state before transmission source terminal 104 transmits a packet is as follows.
The source node device 202 stores the address [133.1.5] of the node device 203 in the area where the terminal 101 is located in the position information table 222.
The terminal 101 moves from the area 213 of the node device 203 to the area 214 of the node device 204, and performs location registration.

The location registration server device 301 updates the node device address associated with the address [1.1.1] of the terminal 101 in the location registration table 311 to the address [133.1.6] of the node device 204.
Steps S1 to S3: The node device 202 adds the address [133.1.5] of the node device 203 to the received user packet 71 addressed to the terminal 101 and transfers it as the inter-node packet 81.
Step S4: Since the destination terminal 101 is not located, the node device 203 searches the server search table 40 and the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 Get.

Step S5: The node device 203 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.1] to the location registration server device 301. At this time, the source node device address of the received packet 81 remains [133.1.4].
Step S6: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located.

Step S7: The location registration server device 301 notifies the address [133.1.6] of the node device 204 in the area where the terminal 101 is located and the destination terminal device 202 to the source node device 202.
Step S8: The node device 202 updates the node device address of the terminal 101 in the position information table 222 to [133.1.6].
As a result, the “local node device address” of the terminal 101 in the location information table 222 of the source node device 202 is updated to the address [133.1.6] of the node device 204 in which the terminal 101 actually exists. Become.

Thereafter, the source node device 202 directly transfers the packet addressed to the terminal 101 to the node device 204.
FIG. 19 shows an embodiment (14) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as that of the embodiment (13) shown in FIG.
In this embodiment (14), first of all, in summary, the receiving-side node device 203 does not directly transfer the inter-node packet 82 to the location registration server device 301, unlike the embodiment (13). A request is made to notify the source node device 202 of the address [133.1.6] of the node device 204 that is in the area and the destination terminal address.

Then, the location registration server device 301 notifies the transmission source node device 202 of the node device address [133.1.6] where the destination terminal is located and the destination terminal address.
Hereinafter, a detailed operation after the destination terminal 101 has moved will be described. The state before the transmission source terminal 104 sends a packet is the same as in the embodiment (13).
Steps S1 to S3: The node device 202 transfers the inter-node packet 81 in which the address [133.1.5] of the node device 203 is added to the received packet 71.

Step S4: Since the destination terminal 101 is not located, the node device 203 searches the server search table 40 and the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 Get.
Step S5: The node device 203 transmits, to the location registration server device 301, a message requesting to notify the transmission source node device 202 of the node device address where the terminal 101 is located and the destination terminal address.

Steps S6 and S7: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located, and uses this and the destination terminal address as the source node. Notify the device 202.
Step S8: The node device 202 updates the node device address of the terminal 101 in the position information table 222 to [133.1.6].

As a result, as in the embodiment (13), the node device 202 can directly transfer the packet 71 addressed to the terminal 101 to the node device 204 in the area where the terminal 101 is located.
FIG. 20 shows an embodiment (15) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as that of the embodiment (14) shown in FIG.
In the present embodiment (15), firstly, the node device 203 on the receiving side is different from the embodiment (14) in that the node device address [133.1.6 The address [133.1.6] is acquired from the location registration server device 301 and transferred to the transmission source node device 202.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described. The state before the transmission source terminal 104 transmits a packet is the same as in the embodiment (14).
Steps S1 to S3: The node device 202 transfers the inter-node packet 81 with the address [133.1.5] of the node device 203 added to the received packet 71 addressed to the terminal 101.
Step S4: Since the destination terminal 101 is not located, the node device 203 searches the server search table 40 and the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101 Get.

Step S5: The node device 203 transmits to the location registration server device 301 a message for inquiring about the node device address where the terminal 101 is located.
Steps S6 and S7: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located, and notifies this to the node device 203.
Step S8: The node device 203 notifies the node device 202 of the address [133.1.6] and the destination terminal address.

Step S9: The node device 202 updates the node device address of the terminal 101 in the position information table 222 to [133.1.6].
Thereby, as in the embodiment (14), the node device 202 transfers the packet addressed to the terminal 101 to the terminal 101.
It becomes possible to transfer directly to the node device 204 in the area.
(iv) Example of Solution 2 for Problem 2 (Example (16) in FIG. 21 to Example (22) in FIG. 27)
In these embodiments, since the location information stored in the source node device is not updated even though the destination terminal has moved, the destination node device is in the service area. Means 2 for resolving the problem of continuing to transmit packets to the former node device (when the destination terminal moves in the area, the location information of the destination terminal stored in the source node device is updated). )) To resolve.

FIG. 21 shows an embodiment (16) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as the configuration of the embodiment (5) shown in FIG. 10, except that the storage unit (cache) 111 of the destination terminal 101 has a transmission source instead of the address of the former node device. Is different from the embodiment (5).
In this embodiment (16), firstly, the node device 204 is configured such that the destination terminal 101 has its own area 214.
, Based on the address stored in the cache 111, the source node device is notified of its own device address [133.1.6] and the destination terminal address all at once.

In general, a terminal may perform packet communication simultaneously with a plurality of terminals. In the embodiments (1) to (15), packet communication from one transmission source terminal to one destination terminal will be described. did.
In this embodiment (16) and later-described embodiments (17) to (22), a case where the destination terminal 101 is communicating simultaneously with the transmission source terminals 103 and 104 will be described.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
The state of the communication system before the destination terminal 101 moves is as follows.
Terminal 101: Located in the area 213 of the node device 203.
The source node devices 201 and 202 store the address [133.1.5] of the node device 203 located in the terminal 101 in the position information tables 221 and 222, respectively.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 in which the transmission source terminals 103 and 104 are located in the cache 111, respectively.
Step S3: The terminal 101 performs location registration with respect to the network. At this time, addresses [133.1.3] and [133.1.4] are notified to the network.

Step S4: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S5: The node device 204 transmits the location registration information to the location registration server device 301.
Steps S6 and S7: The node device 204 notifies the node devices 201 and 202 of the own device address [133.1.6] and the destination terminal address, respectively.

Step S8: The location registration server device 301 updates the visited node device address of the terminal 101 in the location registration table 311 to [133.1.6].
Steps S9 and S10: The node devices 201 and 202 respectively update the node device address of the terminal 101 in the position information tables 221 and 222 to [133.1.6].
Thereafter, the node devices 201 and 202 directly transfer the packet addressed to the terminal 101 to the node device 204 that is the transfer destination in which the terminal 101 is located.

FIG. 22 shows an embodiment (17) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as that of the embodiment (16) shown in FIG. 21, except that the cache 111 of the destination terminal 101 stores the address of the source terminal instead of storing the source node device address. Is different from the embodiment (16).
In the present embodiment (17), first of all, the node device 204 will set the destination terminal 101 in its own area 214.
When the mobile station moves, based on the address stored in the cache 111 of this terminal 101, the transmission source node device indirectly sends its own device address [133.1.6] and the destination terminal address via the location registration server device. Notice.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
The state of the communication system before the destination terminal 101 moves is the same as in the embodiment (16).
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the address [2.1.1] of the transmission source terminal 103 and the address [2.2.1] of the transmission source terminal 104 in the cache 111.

Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [2.1.1] of the source terminal 103 and the address [2.2.1] of the source terminal 104 are notified to the network.
Step S4: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.

Step S5: The node device 204 searches the server search table 40 to obtain the address [133.1.2] of the location registration server device 302 corresponding to the address [2.1.1] of the transmission source terminal 103.
Step S6: The node device 204 searches the server search table 40 to obtain the address [133.1.2] of the location registration server device 302 corresponding to the address [2.2.1] of the transmission source terminal 104. At this time, a location registration server different from that in step S5 may be searched depending on the address of the transmission source terminal.

Step S7: The node device 204 transmits the location registration information to the location registration server device 301.
Step S8: The node device 204 transmits a message to the location registration server device 302 so that the node device 201 in which the transmission source terminal 103 is located notifies the own device address [133.1.6] and the destination terminal address.
Step S9: The node device 204 transmits a message to the location registration server device 302 to notify the node device in which the transmission source terminal 104 is located of its own device address [133.1.6] and the destination terminal address.

Step S10: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Step S11: The location registration server apparatus 302 searches the location registration table 312 and transmits the source terminal 103.
The address [133.1.3] of the node device in the area is obtained.
Step S12: The location registration server apparatus 302 searches the location registration table 312 and sends the source terminal 104.
Get the address [133.1.4] of the node device in the area.

Steps S13 and S14: The location registration server apparatus 302 notifies the node apparatuses 201 and 202 of the address [133.1.6] of the node apparatus 204 and the destination terminal address, respectively.
Steps S15 and S16: The node devices 201 and 202 update the visited node device address corresponding to the terminal 101 in the location information tables 221 and 222 to [133.1.6], respectively.
As a result, the source node devices 201 and 202 know the address [133.1.6] of the node device 204 in which the destination terminal 101 is located, and thereafter, send the packet addressed to the destination terminal 101 to the node device 204.
Can be transferred directly to.

FIG. 23 shows an embodiment (18) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as the configuration of the embodiment (16) shown in FIG. 21 except that the destination terminal 101 does not include the cache 111.
Further, the node device 203 includes a storage unit (cache) 233, and the addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 where the transmission source terminals 103 and 104 are located in the cache 233, respectively. The point that remembers is also different.

In this embodiment (19), firstly, when the destination device 101 moves to its own area 214, the node device 204 will send its own device address [133.1.6] and its own device address [133.1.6] to the source node devices 201 and 202. The destination terminal address is indirectly notified via the location registration server device and the former node device 203.
Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.

The state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.
Each of the location information tables 221 and 222 stores the address [133.1.5] of the node device 203 in the area where the terminal 101 is located.
The cache 233 stores the addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 in which the transmission source terminals 103 and 104 of the destination terminal 101 are respectively located.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network.
Step S3: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.

Steps S5 and S6: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.5] of the node device located in the terminal 101, and the former node device of this address [133.1.5] 203 notifies the node device address [133.1.6] of the destination terminal and the destination terminal address.
Step S7: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].

Steps S8 to S10: The node device 203 notifies the node devices 201 and 202 of the address [133.1.6] of the node device 204 and the destination terminal address.
Steps S11 and S12: The node devices 201 and 202 update the node device address where the terminal 101 is located in the location information tables 221 and 222, respectively, to [133.1.6].
As a result, the source node apparatuses 201 and 202 know the address [133.1.6] of the node apparatus 204 in the area where the destination terminal 101 is located, and thereafter directly transfer the packet addressed to the destination terminal 101 to the node apparatus 204. It becomes possible to do.

FIG. 24 shows an embodiment (19) of the node device according to the present invention which composes the communication system. The configuration of this communication system is the same as the configuration of the embodiment (18) shown in FIG. 23, except that the terminal 101 further includes a storage unit 111 that stores the address of the former node device. ing.
In the present embodiment (19), first, in brief, the node device 204 sets the destination terminal 101 in its own area 214.
Is moved to the source node devices 201 and 202 via the former node device 203 based on the address stored in the cache 111 of the terminal 101, and the device address [133.1.6] Notify the destination terminal address.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
The state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.
The cache 233 stores the address [133.1.3] of the node device 201 where the transmission source terminal 103 of the terminal 101 is located and the address [133.1.4] of the node device 202 where the transmission source terminal 104 is located. .

The source node devices 201 and 202 store the address [133.1.5] of the node device 203 in the area of the terminal 101 in the position information tables 221 and 222, respectively.
Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the address [133.1.5] of the former node device 203 in the cache 111.

Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the former node device 203 is notified to the network.
Steps S4 and S5: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101, and the location registration server device The location registration information is transmitted to 301.

Step S6: The node device 204 notifies the node device 203 of its own device address [133.1.6] and the destination terminal address.
Step S7: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Steps S8 to S10: The node device 203 refers to the cache 233 and notifies the node devices 201 and 202 of the address [133.1.6] of the node device 204 and the destination terminal address.

Steps S11 and S12: The node devices 201 and 202 update the node device address where the terminal 101 is located in the location information tables 221 and 222, respectively, to [133.1.6].
As a result, the node devices 201 and 202 store the address [133.1.6] of the node device 204 located in the terminal 101 in the position information tables 221 and 222, respectively.
Thereafter, the node devices 201 and 202 can directly transfer the packet addressed to the terminal 101 to the node device 204.

FIG. 25 shows an embodiment (20) of the node device according to the present invention which composes the communication system. This embodiment (20) is different from the embodiment (19) shown in FIG. 24 in that the cache 233 of the node device 203 uses the addresses [133.1.3] and [133.1. Instead of storing [4], the address [2.1.1] and [2.2.1] of the source terminal are stored.
In the present embodiment (20), firstly speaking, the node device 204 sets the destination terminal 101 in its own area 214.
Is moved to the source node devices 201 and 202 via the former node device 203 and the location registration server device 302 based on the addresses stored in the cache 111 and the cache 233. .6] and the destination terminal address.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
The state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203. The cache 233 stores the addresses [2.1.1] and [2.2.1] of the transmission source terminals 103 and 104 of the terminal 101. Each of the location information tables 221 and 222 stores the address [133.1.5] of the node device 203 in the area where the terminal 101 is located.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 stores the address [133.1.5] of the former node device 203 in the cache 111.
Is remembered.
Step S3: The terminal 101 performs location registration with respect to the network. At this time, the address [133.1.5] of the former node device 203 is notified to the network.

Steps S4 and S5: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101, and the location registration server device The location registration information is transmitted to 301.
Step S6: The node device 204 notifies the node device 203 of its own device address [133.1.6] and the destination terminal address.

Step S7: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Steps S8 to S10: The node device 203 searches the server search table 40, and the address [133.1.2] of the location registration server device 302 corresponding to the address [2.1.1] of the transmission source terminal 103 stored in the cache 233. Get.

Similarly, the node device 203 obtains the address [133.1.2] of the location registration server device 302 corresponding to the address [2.2.1] of the transmission source terminal 104.
Step S11: The node device 203 transmits a message to the location registration server device 302. In this message, the address [133.1.6] of the node device 204 in the area where the terminal 101 is located and the destination terminal address are located in the area where the source terminal 103 is located. The node device 201 is requested to be notified.

Step S12: Similarly, the node device 203 sends a message to the location registration server device 302 by using the address [133.1.6] of the node device 204 located in the terminal 101 and the destination terminal address of the node device 202 located in the source terminal 104. Ask to be notified.
Steps S13 and S14: The location registration server device 302 searches the location registration table 312 and addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 where the transmission source terminals 103 and 104 are located, respectively. ] Get.

Steps S15 and S16: The location registration server apparatus 302 notifies the node apparatuses 201 and 202 of the address [133.1.6] of the node apparatus 204 and the destination terminal address, respectively.
Steps S17 and S18: The node devices 201 and 202 respectively update the node device address of the destination terminal 101 in the location information tables 221 and 222 to [133.1.6].
As a result, each of the node devices 201 and 202 knows the address [133.1.6] of the node device 204 in which the destination terminal 101 is located, and thereafter directly transfers the packet addressed to the terminal 101 to the node device 204. It becomes possible.

FIG. 26 shows an embodiment (21) of the node device according to the present invention which composes the communication system. This embodiment (21) is different from the embodiment (18) shown in FIG. 23 in that the location registration table 311 of the location registration server device 301 is provided to each destination terminal instead of the node device 203 having the cache 233. A corresponding storage unit (cache) 321 is provided.
This cache 321 is registered in the location registration table 311, for example, the address [133.1.address of the node device 201, 202 where the source terminal 103, 104 that is the communication partner of the destination terminal 101 of the address [1.1.1] is located. 3], [133.1.4] is memorized.

In the present embodiment (21), firstly, the node device 204 will set the destination terminal 101 in its own area 214.
For example, the location registration server device 301 is notified of the own device address [133.1.6] and the destination terminal address to the source node devices 201 and 202 based on the address stored in the cache 321. Ask to do.
Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.

The state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.
The source node devices 201 and 202 store the address [133.1.5] of the node device 203 located in the terminal 101 in the position information tables 221 and 222, respectively.
The cache 321 of the location registration server device 301 stores the addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 where the transmission source terminals 103 and 104 of the terminals 101 and 102 are respectively located. Yes. A method in which the cache 321 stores the address of the source node device will be described later with reference to FIG.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network.
Step S3: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.

Step S5: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Steps S6 to S8: The location registration server device 301 sends the address [133.1.6] of the node device 204 to the node devices 201 and 202 of the addresses [133.1.3] and [133.1.4] stored in the cache 321, respectively.
And the destination terminal address is notified.

Steps S9 and S10: The node devices 201 and 202 respectively update the node device address of the terminal 101 in the position information tables 221 and 222 to [133.1.6].
As a result, the node devices 201 and 202 know the address [133.1.6] of the node device 204 in which the destination terminal 101 is located, and thereafter can directly transfer the packet addressed to the terminal 101 to the node device 204. It becomes possible.

As a modified example of this embodiment (21), the node device 204 registers a message for inquiring about the address of the node device 201 located in the transmission source terminal 103 that is the communication partner of the destination terminal 101 located in the device itself. Send to server device 301.
Then, the location registration server device 301 searches the storage unit 321 and returns addresses [2.1.1] and [2.2.1].

The node device 204 acquires from the location registration server device 302 the addresses [133.1.3] and [133.1.4] of the node devices 201 and 202 where the terminals having the addresses [2.1.1] and [2.2.1] are located. The own device address [133.1.6] and the destination terminal address may be directly transmitted to the node devices 201 and 202.
FIG. 27 shows an embodiment (22) of the node device according to the present invention which constitutes the communication system. The difference between this embodiment (22) and the embodiment (21) shown in FIG. 26 is that the cache 321 stores the address of the transmission source terminal instead of storing the address of the transmission source node device corresponding to the destination terminal. It is to remember.

Another difference is that the location registration server device 301 further includes a server search table 40.
In the present embodiment (22), first of all, the node device 204 will set the destination terminal 101 in its own area 214.
, The location registration server device 301 is requested to notify the source node device 201, 202 of its own device address [133.1.6] and its destination terminal address based on the address stored in the cache 321. .

The operation of this embodiment (22) is the same as that of the embodiment (21), but differs from the operation of the embodiment (21) because the addresses stored in the cache 321 are different.
Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
In the figure, the state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.

Each of the location information tables 221 and 222 stores the address [133.1.5] of the node device 203 in the area where the terminal 101 is located.
The cache 321 stores the addresses [2.1.1] and [2.2.1] of the transmission source terminals 103 and 104 of the terminals 101 and 102. A method in which the cache 321 stores the address of the transmission source terminal will be described later with reference to FIG.

Step S1: The terminal 101 moves to the area 214 of the node device 204.
Step S2: The terminal 101 performs location registration with respect to the network.
Step S3: The node device 204 searches the server search table 40 to obtain the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101.
Step S4: The node device 204 transmits the location registration information to the location registration server device 301.

Step S5: The location registration server device 301 updates the node device address where the terminal 101 is located in the location registration table 311 to [133.1.6].
Step S6: The location registration server apparatus 301 stores the address [2.1.1] of the source terminal 103 of the terminal 101 and the address [2.2.1] of the source terminal 104 in the cache 321.
Step S7: The location registration server device 301 searches the server search table 40 to obtain the address [133.1.2] of the location registration server device 302 corresponding to the address [2.1.1] of the terminal 103.

Step S8: The location registration server device 301 searches the server search table 40 to obtain the address [133.1.2] of the location registration server device 302 corresponding to the address [2.2.1] of the terminal 104.
Step S9: The location registration server device 301 transmits a message to the location registration server device 302. With this message, the node device in the area where the terminal 101 is located is added to the node device in the area where the source terminal 103 is located at the address [2.1.1]. Request notification of the address and the destination terminal address.

Step S10: The location registration server device 301 transmits a message to the location registration server device 302. With this message, the node device located in the terminal 101 is sent to the node device located in the source terminal 104 at the address [2.2.1]. Request notification of the address and the destination terminal address.
Steps S11 and S12: The location registration server device 302 searches the location registration table 312 to obtain node device addresses [133.1.3] and [133.1.4] where the transmission source terminals 103 and 104 are located, respectively.

Steps S13 and S14: The location registration server apparatus 302 notifies the node apparatuses 201 and 202 of the address [133.1.6] of the node apparatus 204 and the destination terminal address, respectively.
Steps S15 and S16: The node devices 201 and 202 respectively update the node device address of the terminal 101 in the position information tables 221 and 222 to [133.1.6].
As a result, the node devices 201 and 202 know the address [133.1.6] of the node device 204 in the area where the destination terminal 101 is located, and thereafter can directly transfer the packet addressed to the terminal 101 to the node device 204. become.

As a modification of the embodiment (22), in steps S4 to S14, the node device 204 may transmit its own device address and the destination terminal address as follows.
The node device 204 transmits a message for inquiring about the address of the transmission source terminals 103 and 104 to the location registration server device 301. The location registration server device 301 returns the addresses [2.1.1] and [2.2.1] stored in the cache 321 to the node device 204.

Then, the node device 204 transmits to the location registration server device 302 a message for inquiring about the node device in which the terminals having the addresses [2.1.1] and [2.2.1] are located. The location registration server apparatus 302 returns the addresses [133.1.3] and [133.1.4] to the node apparatus 204.
Based on the addresses [133.1.3] and [133.1.4], the node device 204 directly transmits its own device address [133.1.6] and the destination terminal address to the source node devices 201 and 202.

In this modification, the location registration server devices 301 and 302 do not require the server search table 40.
(v) Other Embodiments FIG. 28 shows an embodiment (23) of the node device according to the present invention which constitutes the communication system. This embodiment (23) is an embodiment combining the embodiment (1) of FIG. 5 and the embodiment (13) of FIG.
The configuration of the communication system is the same as that of the embodiment (13).

  In the present embodiment (23), first, in summary, the receiving-side node device transmits a packet 81 (packet 71) and a message to the location registration server device. In this message, the receiving-side node device requests that the packet 71 be transferred to the node device in the destination terminal area, and notifies the source node device of the node device address in which the destination terminal is currently located. Ask.

Hereinafter, a detailed operation after the destination terminal 101 has moved will be described.
In FIG. 28, the state of the communication system before the destination terminal 101 moves is as follows.
The terminal 101 is located in the area 213 of the node device 203.
The source node apparatus 202 stores the address [133.1.5] of the node apparatus 203 in which the terminal 101 is located in the position information table 222.

Step S1: The user packet 71 addressed to the terminal 101 arrives at the node device 202.
Step S2: The node device 202 searches the location information table 222 to obtain the address [133.1.5] of the node device 203 in the area where the terminal 101 is located.
Step S3: The node device 202 transfers the inter-node packet 81 to which the address [133.1.5] of the node device 203 is added to the received packet 71 addressed to the terminal 101.

Step S4: Since the destination terminal 101 is not located, the node device 203 searches the server search table 40 and searches for the address [133.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101. ] Get.
Step S5: The node device 203 transfers the packet 71 addressed to the terminal 101 and the inter-node packet 82 including the message information to the location registration server device 301.

FIG. 29 shows a detailed example of the packet 82, and the format of the packet 82 is the same as the packet 82 shown in FIG.
In the fields 91 and 92, the address [133.1.1] of the location registration server device 301 that is the destination of the packet 82 and the address [133.1.5] of the node device 203 that is the source of the packet 82 are displayed, respectively. Yes.

In fields 93 and 94, the address [133.1.1] of the location registration server device 301 that is the destination of the message packet 90 and the address [133.1.5] of the node device 203 that is the source of the message are displayed. Yes.
In the message information field 95, “presence / absence of user packet” = “present” and “message type” = “location information notification, notification destination node device address [133.1.4]” are displayed.

Step S6: The location registration server device 301 recognizes that the message packet 90 is addressed to itself because field 93 = own device address [133.1.1] of the packet 82 received from the node device 203.
Therefore, the location registration server device 301 decrypts the content of the message information field 95,
It is recognized that the user packet 71 addressed to the terminal 101 is included in the message packet 90.

Then, the location registration server device 301 searches the location registration table 311 and the address [133.1. Of the node device 204 in which the terminal 101 of the address [1.1.1] in the destination address field 96 included in the packet 71 is located. 6] is obtained.
Step S7: The location registration server device 301 transfers the inter-node packet 83 in which the address [133.1.6] of the node device 204 is added to the user packet 71 addressed to the terminal 101 to the node device 204.

Step S8: Further, the location registration server apparatus 301 recognizes “address [133.1.4]” of the notification destination in which the “message type” in the message information field 95 is “location information notification”.
Therefore, the location registration server device 301 transmits to the node device 202 a message notifying the address [133.1.6] of the node device 204 in which the terminal 101 is located and the destination terminal address.

Step S9: The node device 202 changes the node device address of the terminal 101 in the position information table 222 to [133.1.6].
As a result, the packet 71 is transferred to the destination terminal 101 via the node device 204. Further, the node device 202 knows the address of the node device 204 in the area where the destination terminal 101 is located.
Thereafter, the node device 202 can directly transfer the packet 71 addressed to the terminal 101 to the node device 204.

FIG. 30 shows a case in which the storage unit of the destination terminal, the storage unit of the node device, and the storage unit of the location registration server device are the transmission sources in the embodiments (16), (18), (19), and (21), respectively. The procedure of storing the address of the node device or the address of the transmission source terminal is shown.
Further, in the embodiments (17), (20), and (22), the procedure in which the storage unit of the destination terminal, the storage unit of the node device, and the storage unit of the location registration server device store the address of the transmission source terminal, respectively. Is shown.

In this figure, as an example of the procedure, when the transmission source terminal 104 transmits a packet 71 to the destination terminal 101, the storage unit 111 of the destination terminal 101, the storage unit 234 of the node device 204 in the area where the destination terminal 101 is located, A procedure for storing the address [2.2.1] of the transmission source terminal 104 or the address [133.1.4] of the transmission source node apparatus 202 in the storage unit 321 of the location registration server apparatus 301 corresponding to 101 is shown.
Note that the configuration of the communication system shown in the figure is the same as the system configuration shown in FIG.

Step S1: The user packet 71 transmitted from the transmission source terminal 104 to the destination terminal 101 arrives at the node device 202.
Step S2: Since the node device 202 does not know the node device address of the destination terminal 101, the node device 202 searches the server search table 40 and searches for the address [1.1.1] of the location registration server device 301 corresponding to the address [1.1.1] of the terminal 101. 133.1.1] is obtained.

Step S3: The node device 202 transfers the inter-node packet 81 in which the address [133.1.1] of the location registration server device 301 is added to the received packet 71 addressed to the terminal 101 to the location registration server device 301.
Step S4: The location registration server device 301 searches the location registration table 311 to obtain the address [133.1.6] of the node device 204 in the area where the terminal 101 is located.

Step S5: At this time, the location registration server apparatus 301 can store the address [2.2.1] of the source terminal 104 in the storage unit 321 by examining the source address of the packet 71.
Further, the location registration server apparatus 301 can store the address [133.1.4] of the node apparatus 202 in which the transmission source terminal 104 is located in the storage unit 321 by examining the transmission source address of the packet 81. .

Step S6: The location registration server apparatus 301 transfers the inter-node packet 82 in which the destination address of the received packet 81 is rewritten to [133.1.6] to the node apparatus 204.
Step S7: Based on the source address [133.1.4] of the packet 81, the location registration server apparatus 301 notifies the node apparatus 202 of the address [133.1.6] of the node apparatus 204 in the terminal 101 area.
Step S8: The node device 202 adds the terminal 101 and its visited node device address [133.1.6] to the location information table 222.

Step S9: The node device 204 can store the address [2.2.1] of the source terminal 104 in the storage unit 234 by examining the source address of the packet 71 included in the received packet 82.
In addition, the node device 204 stores the address [133.1.4] of the node device 202 in which the transmission source terminal 104 is located in the storage unit 234 by examining the transmission source address of the received inter-node packet 82. Can do.

Step S10: When the node device 204 notifies the destination terminal 101 of the address [133.1.4] of the node device 202 in which the transmission source terminal 104 is located, the node device 204 uses the address [133.1.4] of the node device 202. Send the included notification message.
Step S11: The node device 204 transmits the packet 71 from the transmission source terminal 104 to the destination terminal 101.

Step S12: The destination terminal 101 can store the address [133.1.4] of the node device 202 included in the received notification message in the storage unit 111.
The destination terminal 101 receives the user packet 71 transmitted from the transmission source terminal 104. At this time, the destination terminal 101 can store the address [2.2.1] of the transmission source terminal 104 in the storage unit 111 by examining the transmission source address of the user packet 71.

As a result, the storage unit 111, the storage unit 234, and the storage unit 321 store the address [2.2.1] of the transmission source terminal 104 or the address [133.1.4] of the transmission source node device 202, respectively. .
FIG. 31 shows an embodiment (25) of the node device according to the present invention which constitutes the communication system. In this embodiment (25), the node devices 201 to 205 and the location registration server devices 301 and 302 (hereinafter, the node devices 201 to 205 and the location registration server devices 301 and 302 are collectively referred to as node devices) are ATM-SW601 to Connected with 603.

Addresses [1] to [7] are assigned to the node devices 301, 302, and 201 to 205, respectively. As the addresses [1] to [7], VPI / VCI addresses, E.164 addresses, IPv4 addresses, IPv6 addresses, and the like can be used.
As described above, even in a communication system in which a general ATM network is applied to a network between node devices, the IP addresses [133.1.1] of the node devices in the embodiment (1) to the embodiment (23) in FIG. By replacing [133.1.7] with the addresses [1] to [7] of each node device in the ATM network, it is possible to perform packet transfer operations similar to those in the embodiments (1) to (23). is there.

In particular, the ATM-SVC (Switched Virtual
When connecting with (Connection), it is possible that the address of the node device that is the transmission source of the inter-node packet cannot be determined from only the ATM header information. In such a case, it is shown in FIG. 7 and FIG. The method of Example (3) is effective.

FIG. 3 is a block diagram showing an operation principle (1) of the node device according to the present invention. FIG. 6 is a block diagram showing an operation principle (2) of the node device according to the present invention. FIG. 5 is a block diagram showing an operation principle (3) of the node device according to the present invention. FIG. 6 is a block diagram showing an operation principle (4) of the node device according to the present invention. FIG. 3 is a block diagram showing an embodiment (1) of the node device according to the present invention. FIG. 6 is a block diagram showing an embodiment (2) of the node device according to the present invention. FIG. 5 is a block diagram showing an embodiment (3) of the node device according to the present invention. It is the figure which showed the example of a format of the packet used in Example (3) of the node apparatus based on this invention. FIG. 6 is a block diagram showing an embodiment (4) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (5) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (6) of the node device according to the present invention. FIG. 11 is a block diagram showing an embodiment (7) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (8) of the node device according to the present invention. FIG. 12 is a block diagram showing an embodiment (9) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (10) of the node device according to the present invention. FIG. 11 is a block diagram showing an embodiment (11) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (12) of a node device according to the present invention. FIG. 11 is a block diagram showing an embodiment (13) of a node device according to the present invention. FIG. 12 is a block diagram showing an embodiment (14) of the node device according to the present invention. FIG. 11 is a block diagram showing an embodiment (15) of the node device according to the present invention. FIG. 12 is a block diagram showing an embodiment (16) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (17) of the node device according to the present invention. FIG. 18 is a block diagram showing an embodiment (18) of a node device according to the present invention. FIG. 18 is a block diagram showing an embodiment (19) of a node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (20) of the node device according to the present invention. FIG. 10 is a block diagram showing an embodiment (21) of a node device according to the present invention. It is the block diagram which showed the Example (22) of the node apparatus which concerns on this invention. It is a block diagram showing an embodiment (23) of the node device according to the present invention. It is the figure which showed the format example of the packet used in Example (23) of the node apparatus which concerns on this invention. It is the block diagram which showed the Example (24) of the node apparatus based on this invention. FIG. 28 is a block diagram showing an embodiment (25) of a node device according to the present invention. It is the block diagram which showed the structural example of the mobile packet communication system comprised with the common node apparatus. FIG. 10 is a block diagram showing a packet transfer operation example (1) in a conventional mobile packet communication system. FIG. 10 is a block diagram showing a packet transfer operation example (2) in a conventional mobile packet communication system.

101 to 4 Terminal 111 Storage unit, cache
201-5 Node device 211-5 Area
221 to 225 Location information table 233 to 5 Storage unit, cache
301, 302 Location registration server 311, 312 Location registration table
321,322 Storage unit, cache 40 Server search table
501-7 Router 601-3 ATM-SW
71 User packet 81-83 Inter-node packet
90 Message packet (field)
91 Destination address (field) 92 Source address (field)
93 Message destination address (field)
94 Message source address (field)
95 Message information field 96 Destination address (field)
97 Source address (field)
ADR1, ADR2 Location registration server device address
ADR3-7 Node device address In the figure, the same reference numerals indicate the same or corresponding parts.

Claims (3)

  In a node device constituting a communication system together with a terminal and a location registration server device,
  When the destination terminal of the received packet is not located in its own area and knows the address of the node device where the destination terminal is located, the address and the address of the destination terminal are used as the source node device of the packet. If the destination packet is not known, the received packet is transferred to the location registration server device, and the address of the destination node located in the location registration server device and the address of the destination terminal are registered. Requesting the node device of the transmission source to receive the notification.   In a node device constituting a communication system together with a terminal and a location registration server device,
  When the destination terminal of the received packet is not located in its own area and knows the address of the node device where the destination terminal is located, the address and the address of the destination terminal are used as the source node device of the packet. When not knowing, a message requesting to notify the source node device of the address of the destination terminal located in the location registration server device and the address of the destination terminal Is transmitted to the location registration server device.   In a node device constituting a communication system together with a terminal and a location registration server device,
  A storage unit for storing the address of the transmission source terminal;
  The destination terminal has a storage unit for storing the address of the node device in which the destination terminal is located,
  When the destination terminal moves out of its own area, the destination node device address notified by the destination node device of the destination terminal based on the address stored in the storage unit of the destination terminal and the destination terminal And a message including the address of the transmission source terminal stored in the storage unit to the location registration server apparatus, the address of the destination node apparatus to the transmission source node apparatus in which the transmission source terminal is located, and A node device in the destination terminal area, which makes a notification request for the address of the destination terminal.

Images