JP3435360B2 - Mobile computer device, address information management method and address resolution method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to communication while moving on a network in a system composed of a plurality of computers for exchanging data with each other and providing necessary services between a plurality of interconnected networks. The present invention relates to a computer device, an address information management method, and an address resolution method to be performed.

[0002]

2. Description of the Related Art The use of computer systems has rapidly and widely spread to various fields as computer systems have become smaller and less expensive, and network environments have been enhanced. Also, the shift from centralized systems to distributed systems Is progressing. Especially in recent years, not only sharing resources such as files and printers in the office but also communication outside the office and outside the organization (email , E-news, file transfer, etc.) have become possible and these have begun to be widely used. In recent years, in particular, the use of the world's largest computer network “Internet” has become widespread, and it has become popular with external users who connect to the Internet and use publicly available information and services, and vice versa. On the other hand, by providing information and services, new computer business is being cultivated. In addition, new technologies are being developed and deployed regarding the use of the Internet.

With the spread of such networks, technical development for mobile communication is being carried out. In mobile communication, a user having a portable terminal or a computer moves on a network for communication. Sometimes the position on the network is changed while performing communication, and a method for managing the address of the terminal and the computer on the network, which change in such communication, so that the communication content can be correctly reached is necessary.

Techniques for accommodating such a mobile computer or mobile terminal (mobile terminal) in a network have been studied and developed. As such a mobile access technology, there is a method of using Mobile IP. Consider that a user carrying a mobile computer moves on an IP network to communicate. In such communication, when the network address of the mobile computer changes due to the change of the position, a method for managing this and correctly reaching the communication contents is required. Mobile IP is used for this purpose. It

Mobile IP is a technology that makes the mobile computer appear to be at the place where the mobile computer is originally installed (home address of the home network) from other terminals, regardless of where the mobile computer is connected to the Internet. It was standardized as RFC2002 by IETF in October 1996.

The basic operation of Mobile IP will be described below. It should be noted that the operation mode (F
A mode) and an operation mode in which the mobile computer itself also performs packet processing of the foreign agent (Co-loca
Ted Care-of Address mode), but first, the latter Co-located Care-
Mobile I in of Address mode
The basic operation of P will be described with reference to FIGS.

Reference numeral 108 in FIGS. 6 and 7 is a router. The network (home network) 101-1 to which the mobile computer (MH) 105 is originally connected
A router called a home agent (HA) 106 is installed in the. The address (home address) of the mobile computer 105 is "200.0.10.2", and the address of the home agent 106 is "200.0.10.2".
0.10.1 ".

Here, the mobile computer 105 has the home address "200.0.1" of the home network 101-1.
The destination network 101 is moved from the position of 0.2 ".
-2 is assumed to be connected.

Since it is assumed here that the mobile computer 105 itself is in an operation mode that also serves as the packet processing of the foreign agent, the mobile computer 105 uses a mechanism such as DHCP to provide the temporary address (Co-located C).
are-of Address). This temporary address is "200.0.20.1".

The mobile computer 105 notifies the home agent 106 of the IP address "200.0.20.1" of the current position in order to notify the current position of itself. The home agent 106 receiving the request is the mobile computer 1
The correspondence between the home address “200.0.10.2” of 05 and the current position address “200.0.20.1” is managed.

A communication partner (CH) trying to communicate with the mobile computer 105 (107-1 in FIG. 6, 107 in FIG. 7).
-2) does not know that the mobile computer 105 has moved,
The packet is transmitted to the home address “200.0.10.2”. However, since the mobile computer 105 is currently absent at the home address position “200.0.10.2”, the home agent 106 managing the home address sends a packet addressed to this dress “200.0.10.2”. Intercept and use this as the current location address “2
It is encapsulated in an IP packet addressed to 00.0.20.1 "and transferred.

The mobile computer 105 at the address "200.0.20.1" takes out (decapsulates) the packet in the transferred packet, and the packet that is supposed to be received by the home network by itself. Can be received and processed.

From the current position in the opposite direction, the communication partner 107-
When returning the packet to 1, 107-2, the IP packet is directly output to the access source without passing through the home agent 106. At this time, the source address is not the current position "200.0.20.1" but the home address "200.0.10.2". This allows
The mobile computer 105 is also connected to the communication partners 107-1 and 107-2.
Appears to stay connected to the homelink, eliminating the effects of movement.

With such a mechanism, each node on the network can access the mobile computer by using the home address of the mobile computer regardless of where the mobile computer is connected.

Next, the basic operation of Mobile IP in the FA mode in which it is assumed that a foreign agent router exists at the destination will be described with reference to FIG.

The difference from the basic operation described in FIGS. 6 and 7 is that the mobile computer 105 uses the home network 101-1.
When the user moves from the home address “200.0.10.2” of the router and connects to the destination network 101-2, a router (FA) 103 called a foreign agent is installed at the destination (this foreign agent). The address of the agent 103 is "200.0.20.1"
The mobile computer 105 receives a packet addressed to the own device via the foreign agent 103, and the mobile computer 105 uses the address “200.0. 20.1 ″ is notified, and the foreign agent 103 decapsulates the encapsulated packet from the home agent 106 and delivers it to the mobile computer 105 using the link layer address.

In this way, using Mobile IP,
By routing the data packet addressed to the mobile computer, (1) it becomes possible to move across a plurality of subnets. (2) A TCP / IP session can be held when moving. There are advantages such as.

Even when a mobile terminal having a wireless interface is used to change the position on the network while performing communication, the wireless base station switching process (handoff) in the communication with the wireless base station is performed wirelessly. Mobil even when not supported by the data link layer
By using eIP, mobile communication having the above-mentioned advantages can be performed.

By the way, when a computer transmits an IP packet, the IP packet is transmitted using a data link layer address such as a MAC address of a router or another computer which should receive the IP packet next in the subnet. When the IP packet is transferred on this wireless transmission path, the information such as the wireless channel is transferred to the data link. Specified in the layer address). At that time, if the information of the data link layer address corresponding to the IP address of the router or another computer that should receive the IP packet next is not held in the device itself, ARP (Address Resolution)
It is necessary to ask for it by Protocol).

However, when the mobile computer moves across subnets as described above, it moves to a subnet with a node different from the existing subnet, so the logical address-physical address on the subnet The ARP table used to perform the translation (eg IP address to MAC address translation) will be a completely different entry. For this reason, the network module in the mobile computer flushes all ARP tables held by itself and then newly sends out an ARP request message, receives a response message to this, and receives the logical message-physical address It is necessary to reconfigure the ARP table by entering the correspondence information. For this reason, there has been a problem that there is a large overhead until smooth communication can be performed in the destination subnet.

[0021]

Conventionally, Mobile has been used.
When moving across a subnet in the IP system, the only A that the network module in the mobile computer holds
It was necessary to flush and change all the RP tables, resulting in very poor processing efficiency. Especially when there is a terminal near a subnet boundary in wireless media such as a wireless LAN, switching between subnets occurs frequently due to fluctuations in radio wave propagation, and the conventional method of flushing and reconfiguring the ARP table each time There is a problem that a problem that CPU performance is wasted may occur.

The present invention has been made in consideration of the above circumstances, and is a computer system in which a plurality of computers are connected to each other by a plurality of interconnected communication networks so that they can communicate with each other. It is an object of the present invention to provide a mobile computer device, an address information management method, and an address resolution method capable of executing high-speed address resolution processing without flushing the ARP table when performing communication at the destination.

[0023]

The present invention (Claim 1) includes:
A mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, and a correspondence relationship between a link layer address of a node acquired on the moved sub-network and its network layer address. It is characterized by further comprising means for storing information and means for deleting, among the correspondence information, information corresponding to a condition that a predetermined condition is satisfied after movement between sub-networks.

[0024] Preferably, the predetermined condition may be that a predetermined time has elapsed since the correspondence information was created. The present invention (claim 3) is
A mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, and a correspondence relationship between a link layer address of a node acquired on the moved sub-network and its network layer address. Means for storing information, means for detecting that the own computer has moved from a sub-network to which it has belonged to a different sub-network, and one corresponding to the sub-network to which it has belonged among the correspondence information To
Means for deleting after a lapse of a predetermined time from the detection of the movement.

According to the present invention (claim 4), there is provided a mobile computer device capable of moving between a plurality of sub-networks connected to each other to perform communication. A means for storing the correspondence information between the link layer address and the network layer address, a means for creating and storing management information for managing the correspondence information for each sub-network, and the own computer belongs to that time. Means for detecting that the sub-network has moved from one sub-network to another sub-network,
When the movement is detected, it is provided with means for checking whether or not the management information corresponds to the moved sub-network, and if not, creating corresponding management information. It is characterized by that.

The present invention (claim 5) is a mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, wherein The storage unit that stores the correspondence information between the link layer address and the network layer address and the management information for managing the information for accessing the correspondence information for each sub-network, and the own computer Means for detecting the movement from the sub-network to which it has belonged to a different sub-network, and when the movement is detected, there is one corresponding to the moved sub-network in the management information. On the moved sub-network and a means for checking whether or not it exists, and creating corresponding management information if it does not exist. Means for obtaining the link layer address of the node from the correspondence information of the node accessed based on the management information when transferring the packet to the node, and the correspondence information of the node transferring the packet. If not, the link layer address of the node obtained by making an inquiry based on the network layer address is stored in the node, and the management information is updated.

Preferably, a means for deleting the correspondence information or the correspondence information and the management information when a predetermined condition is satisfied may be further provided. The present invention (claim 7) is an address information management method in a mobile computer device capable of moving between a plurality of sub-networks connected to each other for communication.
The correspondence information between the link layer address of the node and the network layer address acquired on the moved sub-network is stored, and among the correspondence information, the one that reaches a predetermined condition after moving between sub-networks is stored. It is characterized by deleting.

The present invention (claim 8) is a method of managing address information in a mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other. Stores the correspondence information between the link layer address of the node and its network layer address obtained in step 1, detects that the computer has moved from the sub-network to which it belongs to a different sub-network, and among the correspondence information It is characterized in that the one corresponding to the sub-network to which it has belonged is deleted after a predetermined time has elapsed after the movement was detected.

The present invention (claim 9) is a method for managing address information in a mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other. It stores the correspondence information between the link layer address of the node and the network layer address obtained in 1., manages the correspondence information for each subnetwork, and the subnetwork which is different from the subnetwork to which the computer belongs until then. When the movement is detected, if the movement is detected, it is checked whether or not there is one corresponding to the moved subnetwork in the management information. It is characterized by creating.

The present invention (claim 10) is an address resolution method in a mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other. The correspondence information between the acquired link layer address of the node and its network layer address is stored, and the management information for managing the information for accessing this correspondence information for each sub-network is stored. Has moved to a different sub-network from the sub-network to which it belonged, and when the movement is detected, whether or not there is one corresponding to this moved sub-network in the management information. Check that the corresponding management information is created if it does not exist, and the node is moved to a node on the moved sub-network. When transferring Tsu bets, it searches the correspondence information corresponding to the node based on said management information,
If there is correspondence information of the node that transfers the packet, the link layer address of the node is obtained from the correspondence information, and if the correspondence information of the node does not exist, the node is based on the network layer address. It is characterized in that an inquiry is made to obtain the link layer address of the node.

It should be noted that the present invention related to the apparatus is established as an invention related to the method, and the present invention related to the method is also established as an invention related to the apparatus. Further, the present invention relating to an apparatus or a method is provided for causing a computer to execute a procedure corresponding to the present invention (or for causing a computer to function as means corresponding to the present invention, or for a computer to have a function corresponding to the present invention. It also holds as a computer-readable recording medium in which a program (for realizing it) is recorded.

According to the present invention, the ARP processing is performed by using a single ARP table, and a plurality of retained ARP entries can be stored without performing the processing such as flushing the ARP table and new allocation each time when moving across the subnet. By switching for each subnet (holding ARP entries at multiple destinations, checking the management data structure at each destination, and if ARP entry data for the corresponding subnet has already been saved , By using it), it is possible to perform high-speed address resolution processing that minimizes the overhead of information switching accompanying movement, without performing extra flushing of ARP entries in the movement destination network as is conventionally done.

According to the present invention, high-speed address resolution processing can be realized without extra flushing of ARP entries in the destination network. Further, according to the present invention, when the control of the mobile computer by Mobile IP is applied, efficient ARP entry processing can be executed even under the environment of limited processor and memory resources.

[0034]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example of the basic configuration of the mobile computer 20 according to this embodiment. This mobile computer 20
Has an address acquisition processing unit 1, a movement registration processing unit 2, a packet processing unit 3, a packet transmission / reception unit 4, a movement detection unit 5, and an address resolution processing unit 6.

Here, the mobile computer 20 is shown in FIG.
Co-located that decapsulates the packet without the foreign agent described in
Mo operating in Care-of Address mode
It is assumed that the mobile phone has a function as a mobile node of the bile IP.

The address acquisition processing unit 1 uses a means such as DHCP to co-locate the Mobile IP.
It is a unit for acquiring d Care-of Address. According to Mobile IP, I transferred from the home agent (106 in FIG. 6 / FIG. 7)
The source of the outer IP header of the P-in-IP format packet is this “home agent”, and the destination is the “Co-located Care-of Addr” acquired here.
ss ”.

The movement registration processing unit 2 acquires the Care-
Home Agent 1 based on of Address
Mobile IP registration with Reg. 06 (Regis
This is a unit for exchanging messages.

The packet processing unit 3 is a unit for performing packet processing such as decapsulation processing of IP-in-IP format packets transferred from the home agent 106 and generation processing of packets to be transmitted. In addition,
With respect to the packet originating from the own device, the home address of the own device is used as a source address to generate and transmit the packet.

The packet transmitting / receiving unit 4 is a unit for transmitting the packets generated by the above-mentioned units to the network and receiving the packet transmitted from the network to its own device.

The movement detection unit 5 is a unit for detecting that the own device has moved to a subnet different from that before and notifying the other units of this. Where M
The following methods are shown in RFC2002 as a method for detecting movement across subnets in the mobile IP method. (A) If it is certain that the foreign agent exists in the destination network, the foreign agent receives an agent advertisement message periodically broadcast to the subnet, examines the network address of the source address of this foreign agent message, and checks another network. Decide to move to. (B) If it is certain that the foreign agent exists in the foreign network, the mobile node sends an agent solicitation message (Agent Solicitation) to search for the foreign agent,
The network address of the foreign agent address that responds to this is checked to detect that it has moved to another network. (C) Although not written in RFC2002, even if the source of a packet such as ARP flowing in the destination network is looked at and the network address portion thereof is examined to presume that it has moved to another network, Good (but sometimes it's better not to use).

Here, the movement detecting section 5 uses the method (a) described above, and if movement between subnets is detected, it notifies each unit of the network address information of the new subnet.

A function of instructing that the user has moved to a different subnet may be provided. The address resolution processing unit 6 is a module for performing address resolution processing. For example, normal TCP / IP uses ARP (Add).
This can be realized by extending a module that performs address resolution processing called "reslation Resolution Protocol".

Here, when the movement detection unit 5 detects the movement between the subnets of its own device and notifies it, the address resolution processing unit 6 accesses the data structure called the subnet management data structure and If the own device holds the ARP entry for the subnet, it is used as it is to perform the address resolution process.

FIG. 2 shows an example of the structure of the subnet management data structure. As shown in FIG. 2, this subnet management data structure has subnet information lists 611-6.
13 and ARP entry lists 621 to 624.

Here, the state is shown after the mobile computer 20 has moved through three subnets. That is, FIG.
Middle, subnet information list 61 at the top position of the list
1 and the ARP entry lists 621 and 622 correspond to the current subnet, and the subnet information list 612 and the ARP entry list 6 linked to the subsequent stage.
23 corresponds to the previously connected subnet, and further, the subnet information list 613 and the ARP entry list 623 linked to the subsequent stage correspond to the previously connected subnet. .

Subnet information linked list 611-
Reference numerals 613 denote attribute information such as a network address and a netmask of each subnet, information about a node in the subnet such as an IP address of a default router if necessary, and ARP entries 621 to 624 included in each subnet. And a pointer to.

Each of the ARP entries 621 to 624 includes pair information of the IP address and MAC address of each router or computer. It should be noted that each ARP entry is connected in a list in order to efficiently perform ARP timeout processing.

Although FIG. 2 shows an example in which each subnet management data structure is sequentially connected by the linked list, the subnet management data structure after movement exists in the linked list when movement is detected. In order to search whether or not to perform the search, for example, if a hash function is used with the network address as a key, the search can be performed efficiently.

The mobile computer 20, when the movement is detected,
Following the linked list of subnet information, if there is corresponding subnet information, ARP processing is started using it. If there is no corresponding subnet information, a new subnet information entry is created, a new ARP entry is created, and processing is performed.

Next, the deletion of the ARP entry will be described. In the present embodiment, when the movement is detected, the address resolution processing unit 6 holds the AR currently held at that time.
The P entry is not flushed and is deleted later.

Various variations can be considered as the method of deleting the ARP entry. This is shown below. (1) After a predetermined time has passed from the time when the movement was detected,
Delete the subnet information list and all ARP entries for the subnets that were previously connected.

(2) After the lapse of a predetermined time from the time when the movement is detected, all the ARP entries for the subnets connected until then are deleted. Do not delete the subnet information list and keep it. For specific nodes, such as home agent, foreign agent, default router, etc., set a special flag to prevent them from being deleted, or delete them later than the specified time. Good.

(3) For each ARP entry, a predetermined lifetime is set when the ARP entry is created, and the ARP entry is deleted when the lifetime expires. The subnet information list is retained without being deleted (the subnet information list may be deleted when all the ARP entries to be linked are deleted). Note that certain nodes, such as home agents, foreign agents, default routers, etc., should not be deleted by setting a special flag or setting the lifetime to a value equivalent to infinity. Alternatively, the lifetime may be set to a larger value so that it is deleted later.

(4) If possible in terms of storage capacity, delete all or part of the subnet information list and ARP entry (for example, the subnet that the user explicitly or specifies the relevant conditions). You may make it hold | maintain instead.

Next, the processing when the movement is detected will be described. FIG. 3 shows an example of a processing procedure at the time of movement detection. When the movement is detected, it is checked whether or not there is the corresponding subnet information in the linked list of the subnet information (step S1), and if there is no corresponding subnet information, the subnet information is created (step S2), and the creation / creation is performed. The retrieved subnet information is placed at the head of the subnet list (step S3), and Mobile IP registration processing is performed (step S4).

The information such as the IP address of the router existing in the subnet is, for example, an advertisement message broadcast by the router itself in the subnet or DH.
A method of acquiring from the response message from the CP can be considered.

On the other hand, if there is the relevant subnet information in the linked list of subnet information, the created / searched subnet information is placed at the head of the subnet list (step S3), and Mobile IP registration processing is performed (step S4). .

Next, the processing at the time of packet transmission will be described. FIG. 4 shows an example of a processing procedure at the time of packet transmission. When transmitting a packet, it is checked whether or not there is a corresponding ARP entry (step S11), and if there is no ARP entry, an ARP request is transmitted (step S1).
2). Sleep until time-out (step S1
(Loop of 3 to S15), if an ARP reply is received before the timeout, an ARP entry is created and AR
While linking to the P entry list, a pointer to this ARP entry is registered in the corresponding subnet information (step S16). And the created / searched ARP
Create a transmission packet using the entry (step S
17), packet transmission is performed (step S18). If a timeout occurs before receiving the ARP reply, an error will occur (step S19).

On the other hand, if there is an ARP entry, a transmission packet is created using the created / searched ARP entry (step S17) and packet transmission is performed (step S).
18).

As described above, according to the present embodiment, the ARP processing is performed by using a single ARP table, and a plurality of ARP tables are flushed and new allocations are not performed each time a movement across a subnet is performed. By switching the retained ARP entry information for each subnet (holding ARP entries at a plurality of destinations, checking the management data structure of each destination,
If ARP entry data for the corresponding subnet is already stored, use it),
It is possible to perform high-speed address resolution processing that minimizes the overhead of information switching due to movement without performing extra flushing of ARP entries in the movement destination network as in the conventional case.

Therefore, according to the present embodiment, the Mobi
When the control of the mobile computer by le IP is applied,
Efficient ARP entry processing can be executed even under the environment of limited processors and memory resources.

Next, the mobile computer 20 functions as a mobile node of Mobile IP operating in FA mode assuming that a router called a foreign agent (103 in FIG. 8) exists at the destination described with reference to FIG. In the case of having it, Co-1
Description will be made focusing on the points different from those related to the Occurred Care-of Address mode.

The address acquisition processing unit 1 carries out the Care-of contained in the advertisement packet from the foreign agent.
Address is used as a temporary address. Based on the acquired temporary address, the mobile registration processing unit 2 exchanges the MobileIP registration message with the home agent (106 in FIG. 8) via the foreign agent 103.

The packet processing unit 3 differs from the one described above in that the IP-in-IP format packet transferred from the home agent 106 is not decapsulated (the foreign agent 103 performs this decapsulation process). ).

The packet transmitting / receiving unit 4 is the same as that described above. The movement detection unit 5 basically uses one of the methods (a) to (c) described above, and if movement between subnets is detected, the network address information of the new subnet is sent to each. Notify the unit. In addition, a function of instructing that the user has moved to a different subnet may be provided.

However, Co-located Care
If the mixture of -of Address mode and FA mode is allowed, if there is no foreign agent in the movement-destination subnet, the above method (a) or the instruction from the user is used.

The address resolution processing unit 6 acquires the IP / MAC included in the foreign agent only from the response message to the agent advertisement message or the agent request message from the foreign agent instead of the ARP.

In FA mode, the mobile computer is the MAC of the foreign agent except for the home net.
Only the address needs to be held, so for subnets other than the homenet, 1 for each subnet information
Only one ARP entry (IP address / MAC address of the foreign agent) will be linked.

Further, the IP address of the foreign agent may be registered in the subnet information. The process at the time of movement detection and the process at the time of packet transmission are basically the same as those described above.

Next, an example in which this embodiment is effective will be described with reference to FIG. In the network illustrated in FIG. 5, a plurality of routers (not shown) having a function of transferring data packets transferred via the respective wireless base stations (30-1, 30-2) to the Internet 1 are installed, Multiple subnets (# 1, #
2) are connected to each other. Then, each router is mapped to a network corresponding to one subnet. While the wireless mobile terminal 20 is moving within a certain geographical range covered by a predetermined number of wireless base stations, the wireless mobile terminal 20 belongs to the same subnet and its IP address is also constant. Although not changing, when the wireless mobile terminal 20 moves between wireless base stations accommodated in different routers (for example, between the wireless base station 30-1 and the wireless base station 30-2), the IP address is replaced. A new mobile registration process for Mobile IP and Mobile IP is required.

As illustrated in FIG. 5, two or more radio base stations (30-1, 30-in FIG. 5) that are geographically adjacent to each other and are mapped to different subnets in the wireless LAN. The mobile computer 20 that has moved to the boundary portion of 2) frequently moves between two or more subnets depending on the radio wave condition.

In such a case, in the conventional case, the ARP table was frequently flushed depending on the above radio wave condition, which was very inconvenient. However, according to the present embodiment, the ARP entry can be executed at high speed. By switching to, it is possible to efficiently start the address resolution processing.

As described above, according to the present embodiment, when the control of the mobile computer by Mobile IP is applied, the efficient ARP entry processing is performed even under the environment of the limited processor and memory resources. Can be executed.

Each of the above functions can be realized as software. Further, the present embodiment is readable by a computer in which a program for causing a computer to execute a predetermined means (or for causing a computer to function as a predetermined means or for causing a computer to realize a predetermined function) is recorded. It can also be implemented as a recording medium.

The present invention is also applicable to mobile communication protocols other than Mobile IP. The present invention is
The present invention is not limited to the above-described embodiment, and various modifications can be made within the technical scope of the invention.

[0076]

According to the present invention, without extra flushing of ARP entries in the visited network,
Address resolution processing can be realized at high speed.

[Brief description of drawings]

FIG. 1 is a diagram showing a basic configuration example of a mobile computer according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration example of a subnet management data structure.

FIG. 3 is a flowchart showing an example of a processing procedure when movement is detected.

FIG. 4 is a flowchart showing an example of a processing procedure at the time of transmission.

FIG. 5 is a diagram for explaining an operation example in a wireless network.

FIG. 6 is a diagram for explaining the basic operation of Mobile IP.

FIG. 7 is a diagram for explaining the basic operation of Mobile IP.

FIG. 8 is a diagram for explaining the basic operation of Mobile IP.

[Explanation of symbols]

1 ... Address acquisition processing unit 2 ... Movement registration processing unit 3 ... Packet processing unit 4 ... Packet transmitter / receiver 5 ... Movement detector 6 ... Address resolution processing unit 20 ... Mobile calculator

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Yokoyama, No. 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Fuchu factory, Toshiba Corporation (56) References JP-A-8-172669 (JP, A) JP-A-8- 265358 (JP, A) JP 10-51449 (JP, A) JP 10-32597 (JP, A) JP 9-261265 (JP, A) JP 8-331150 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 12/00 H04B 7/26

Claims (10)

(57) [Claims] 1. A mobile computer apparatus capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer address of a node acquired on the moved sub-network and its network layer. A means for storing correspondence information with an address; and a means for deleting, from the correspondence information, information that has reached a predetermined condition after movement between sub-networks. Mobile computing device to do. 2. The mobile computer device according to claim 1, wherein the predetermined condition is that a predetermined time has elapsed since the correspondence information was created. 3. A mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer address of a node acquired on the moved sub-network and its network layer. A means for storing the correspondence information with the address, a means for detecting that the own computer has moved from a sub-network to which it has belonged to a different sub-network, A mobile computer device, comprising: means for deleting one corresponding to a network after a predetermined time has elapsed from the detection of the movement. 4. A mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer address of a node acquired on the moved sub-network and its network layer. Means for storing correspondence information with addresses, means for creating and storing management information for managing the correspondence information for each sub-network, and a sub-network different from the sub-network to which the computer has belonged until then. Means for detecting movement to a network, and when the movement is detected, it is checked whether or not there is one corresponding to the moved sub-network in the management information, and if it does not exist. A mobile computer device comprising means for creating corresponding management information. 5. A mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer address of a node acquired on the moved sub-network and its network layer. Storage means for storing correspondence information with addresses and management information for managing the information for accessing the correspondence information for each sub-network, and the sub-network to which the own computer belongs until then. Means for detecting that the subnetwork has moved to a different subnetwork, and if the movement is detected, it is checked whether or not there is one corresponding to the moved subnetwork in the management information. Otherwise, a means to create the corresponding management information and a packet to a node on the moved subnetwork. When transferring the packet, the means for obtaining the link layer address of the node from the correspondence information of the node accessed based on the management information, and the correspondence information of the node transferring the packet do not exist. And a means for storing the link layer address of the node obtained based on the network layer address in the node and updating the management information. 6. The movement according to claim 4 or 5, further comprising means for deleting the correspondence relationship information, or the correspondence relationship information and the management information, when a predetermined condition is satisfied. Computer equipment. 7. A method for managing address information in a mobile computer device capable of moving and communicating between a plurality of sub-networks connected to each other, the link layer of a node acquired on a moved sub-network. An address characterized by storing correspondence information between an address and its network layer address, and deleting, of the correspondence information, information that has reached a predetermined condition after movement between sub-networks. Information management method. 8. A method of managing address information in a mobile computer apparatus capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer of a node acquired on a moved sub-network. The correspondence information between the address and its network layer address is stored, and it is detected that the own computer has moved from a subnetwork to which it belongs to a different subnetwork. The address information management method, wherein the address information management method is deleted after a predetermined time has elapsed since the movement was detected. 9. A method of managing address information in a mobile computer apparatus capable of moving and communicating between a plurality of sub-networks connected to each other, wherein a link layer of a node acquired on a moved sub-network. The correspondence information between the address and its network layer address is stored, and the correspondence information is managed for each sub-network, and it is detected that the own computer has moved from the sub-network to which it belongs to a different sub-network. When the movement is detected, it is checked whether or not the management information corresponding to the moved sub-network exists, and if not, the corresponding management information is created. Address information management method. 10. A method for address resolution in a mobile computer device capable of moving between a plurality of sub-networks connected to each other for communication, comprising a link layer address of a node acquired on a moved sub-network. And the network layer address correspondence information, and the management information for managing the information for accessing this correspondence information for each sub-network. It is detected that the network has moved to a different sub-network, and when the movement is detected, it is checked whether or not there is one corresponding to the moved sub-network in the management information, and if it does not exist. When creating corresponding management information and forwarding the packet to a node on the moved sub-network , Searching the correspondence information corresponding to the node based on the management information, and if there is correspondence information of the node that transfers the packet, obtains the link layer address of the node from the correspondence information, and then the correspondence of the node If there is no relation information, the address resolution method is characterized in that the node is queried based on its network layer address to obtain the link layer address of the node.