JP2003018185A - Mobile ip communication system, mobile ip communication method, network repeater system and terminal for mobile object - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable 'mobile IP communication', in an environment where IP networks using the plurality of versions of IP protocols coexist. SOLUTION: A terminal 10 for a traveling object is provided with a registration request packet generating means 17 for generating a registration request packet for registering the coexistent noticed address (IPV6 ) in a home agent 50 and registration request packet transmitting means 18 and 19 for encapsulating and transmitting the registration request packet, according to IP route control information with the IPV4 address of the terminal 10 of the traveling object as a transmission origin address, and with the IPV4 address of the home agent as destination address. A network repeater system 30 is provided with a transmission origin address converting means 33, for converting the transmission origin address of the IP route control information in the registration request packet into the coexisting care-of address (IPV6 ).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for performing "mobile IP communication" in an environment in which "TCP / IP communication networks (hereinafter referred to as IP networks)" using a plurality of versions of IP protocols are mixed. .

[0002]

2. Description of the Related Art In recent years, the number of terminals used per user has been increasing due to the spread of the Internet that carries TCP / IP communication services and the downsizing and price reduction of terminals. , IPv4) "
In, there is a serious problem of exhaustion of IP addresses. Therefore, the address space of the IP address is 3
The specification and development of the "new IP protocol (IP version 6, IPv6)", which tries to solve the problem by expanding from 2 bits to 128 bits, is underway.

However, the IP protocol used by all terminals on the Internet is "IPv6" at once.
Transitioning to is difficult because it involves various problems. Therefore, in the future I
In order to connect P networks to each other, between IP networks using different versions of IP protocol,
It is necessary to provide a seamless TCP / IP communication service.

In order to solve this problem, a standardization committee on the Internet, "IETF (Inter
net Engineering Task Forc
"e)", "IP version number conversion method" as a technique for gradually migrating the version of the IP protocol
Has been studied and developed.

[0005]

However, the above-mentioned IP version number conversion method is used for the I version of a plurality of versions.
It does not consider performing "mobile IP communication" in an environment in which IP networks using the P protocol are mixed.

[0006] Here, "mobile IP communication" means "home network" in which a mobile terminal gives an IP address to the mobile terminal.
k) ”to another IP network and the destination IP network“ Foreign Network ”has given a new IP address to the mobile terminal. Even if there is, an IP packet whose destination address is the IP address of the mobile terminal given by the “home network” can be “routed” to the mobile terminal. . In "MobileIP", which is being considered by IETF as one of the "mobile IP communication" methods, when a mobile terminal (mobile node) moves from a "home network" to a "visited network", the mobile terminal concerned But "Mob
ileIP registration request message ", the" visited agent (Foreig) "on the" visited network "is used.
n Agent) "or the" Co-locate Care-of Address (Co-locate) of the mobile terminal newly assigned by the DHCP service of the "visited network".
"d Care-of-Address)" is registered in the "home agent" as a "care-of-address". After that, the IP packet addressed to the mobile terminal transferred to the "home agent" is delivered to the "visited network" using tunneling transfer.

That is, the above-mentioned translator for "IP version number conversion method" arranged in the relay nodes (routers) of "home network" and "visited network" using different IP protocols,
Since it is not possible to manage the address translation information related to the mobile terminal whose assigned IP address is frequently changed, "M
Even after the "care-of address" is registered in the "home agent" by the "mobileIP registration request message", the IP packet addressed to the mobile terminal cannot be routed. As a result, "MobileIP"
If the continuity of the communication to be supplied in step 1 is not satisfied and the mobile terminal moves between IP networks using different versions of the IP protocol, the communication will be interrupted.

Therefore, the present invention has been made in view of the above points, and it is possible to perform "mobile IP communication" in an environment in which IP networks using a plurality of versions of IP protocols are mixed. It is an issue.

[0009]

[MEANS FOR SOLVING THE PROBLEMS] Mobile I according to the present invention
A P communication system and a mobile IP communication method are a mobile terminal, a home agent managing a first IP address of a mobile terminal allocated in a first network, a first network and another network. A network relay device for connecting two networks, wherein the network relay device has a first network assigned to the first network.
The second IP address of the home agent received from the mobile terminal via the second network in the address conversion table that stores the IP address of the home agent and the second IP address assigned in the second network in association with each other. The home agent's first IP address and home agent's second IP address
And storing the IP address of the first network and the second network based on the address conversion table.
And the step of translating the address in the IP packet transmitted / received to / from the network.

According to the mobile IP communication system and the mobile IP communication method of the present invention, the network relay device receives the “second IP address (IP of the home agent) received from the mobile terminal via the second network.
v4 address) inquiry (DNS inquiry) "in association with the" home agent first IP address (IPv6 address) "and the" home agent second IP address (IPv4 address) ". Since it is stored in the IP address of the home agent, the IP address of the home agent can be converted between the IP network using IPv6 and the IP network using IPv4.

A mobile IP communication system and a mobile IP communication method according to the present invention include: a mobile terminal;
A home agent that manages the first IP address of the mobile terminal assigned to the second network, and a network relay device that connects the first network and a second network that is another network. , The first address system of the first IP address assigned in the first network is different from the second address system of the second IP address assigned in the second network, and Generating a registration request packet for registering the third IP address of the mobile terminal, which is obtained by converting the second IP address of the mobile terminal according to the first address system, with the home agent; The second IP address of the home agent with the second IP address as the source address A step of encapsulating and transmitting the registration request packet by the IP route control information used as the destination address, and the source address in the IP route control information in the registration request packet transmitted by the mobile terminal in the network relay device. Is converted into the third IP address of the mobile terminal according to the first address system.

According to the mobile IP communication system and the mobile IP communication method of the present invention, the network relay device sets the transmission source address in the IP route control information in the registration request packet transmitted by the mobile terminal as “mobile terminal. Third IP address of (Coexistence care of address (IP
v6)) ”, and the home agent registers this“ third IP address of the mobile terminal (coexistence care of address (IPv6)) ”. The network relay device can generate the "second IP address (IPv4 address) of the mobile terminal" by a predetermined method from the "third IP address of the mobile terminal (coexistence care of address (IPv6))". Therefore, it is possible to maintain continuity of mobile IP communication even in an environment in which an IP network using IPv6 and an IP network using IPv4 coexist.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION (Configuration of Mobile IP Communication System According to Embodiment) An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram showing a mobile IP communication system according to this embodiment. As shown in the figure, the mobile IP communication system according to the present embodiment has an IP network (first network) 1 using IPv6 and an IP network (second network) using IPv4.
The “mobile IP communication” is provided to the mobile terminal 10 moving between the mobile terminal 10 and the mobile terminal 10. I
The P network 1 is a “home network 1” in which address information related to the mobile terminal 10 is registered,
The IP network 2 is an IP to which the mobile terminal 10 moves.
It is the "visited network 2" that is the network.

The mobile IP communication system according to this embodiment is specifically, a mobile terminal 10, a network relay device 30, a home agent 50, a visited agent 51, a DHCP server 52, and a wireless relay device. And 53.

The mobile terminal 10 is composed of, for example, a mobile phone terminal, a PHS terminal, etc.
It has a function of processing communication. Mobile terminal 1
0 is, specifically, as shown in FIG.
, Protocol detection unit 12, HA IPv4 address acquisition unit 13, IPv6 address information storage unit 14, mobile terminal IPv4 address acquisition unit 15, and mobile terminal I
A Pv6 generation unit 16, a registration request packet generation unit 17,
The transfer packet generator 18 and the transmitter / receiver 19 are provided. The registration request packet generation unit 17 constitutes a registration request packet generation means. The transfer packet generator 18 and the transmitter / receiver 19 constitute a registration request packet transmitter.

The movement detecting section 11 includes a protocol detecting section 12
The mobile terminal 10 is connected to an IP network, detects the movement of the mobile terminal 10 between the IP networks, and notifies the protocol detection unit 12 to that effect. The movement detection unit 11 may, for example,
MP (Internet Control Manager)
"Router Advertisement message" of "Element Protocol"
Message), the mobile terminal 10
Determines if it has moved between IP networks.

The protocol detection unit 12 includes a movement detection unit 11
It is connected to the HA IPv4 address acquisition unit 13 and determines whether the visited network 2 uses “IPv4” or “IPv6” according to the notification from the movement detection unit 11. The protocol detection unit 12 inspects, for example, the "router advertisement message" of "ICMP", and the visited network 2 determines that "IPv4".
IP network using IP or IP using "IPv6"
Determine if it is a network. The protocol detection unit 12 is
The determination result is notified to the HA IPv4 address acquisition unit 13.

The HA IPv4 address acquisition unit 13 includes a protocol detection unit 12 and an IPv6 address information storage unit 14.
And a registration request packet generator 17
Using the “host name of the home agent 50” stored in the Pv6 address information storage unit 14, the “IPv4 address of the home agent 50” is acquired from the DNS function unit 37 of the network relay device 30, and the “home agent 50” is acquired. The IPv4 address of the ".

The IPv6 address information storage unit 14 is a HA
It is connected to the IPv4 address acquisition unit 13 and the registration request packet generation unit 17, and has address information (IPv6 address, host name, etc.) related to the mobile terminal 10 and address information (IPv6 address, host name, etc.) related to the home agent 50. ) Is remembered.

Mobile terminal IPv4 address acquisition unit 15
Is connected to the movement detection unit 11 and the mobile terminal IPv6 generation unit 16, and the movement detection unit 11 causes the mobile terminal 1 to move.
When the movement between the IP networks of 0 is detected, the DHCP server 52 of the visited network 2 reports “IPv4 address assigned to the mobile terminal 10 (IPv4 address of the mobile terminal 10, second IP address ) ”Is obtained.

The mobile terminal IPv6 generation unit 16 is connected to the mobile terminal IPv4 address acquisition unit 15 and the registration request packet generation unit 17, and is acquired by the mobile terminal IPv4 address acquisition unit 15. I of 10
"IPv4 of mobile terminal 10" based on the "Pv4 address"
6 addresses (coexistence care-of address (IPv6), mapped address (IPv6), third IP address) ”are generated. The "IPv6 address of the mobile terminal 10" is 128 bits, and the "IPv6 address of the mobile terminal 10"
Since "4 address" is 32 bits, "mobile terminal 1
0 IPv6 address (128 bits) ”is generated by
"IPv4 address of mobile terminal 10 (32 bits)"
Is added by adding a predetermined prefix.

The registration request packet generator 17 has the HA I
The mobile terminal IPv4 address acquisition unit 15 is connected to the Pv4 address acquisition unit 13, the IPv6 address information storage unit 14, and the mobile terminal IPv6 address generation unit 16.
"Registration request packet" for registering the "IPv6 address of the mobile terminal 10", that is, the "coexistence care-of address (IPv6)" acquired by the mobile terminal IPv6 generation unit 16 in the home agent 50.
Is generated.

The "registration request packet" is composed of an IPv6 header having routing control information for IPv6 protocol, an authentication header, and a receiver option header.
The “registration request packet” is an IPv6 header
The “IPv6 of the mobile terminal 10” generated by the mobile terminal IPv6 address generation unit 16 as the “source address”
6 addresses ”, that is,“ coexistence care address (IPv6
6) ”is set, and the“ IPv6 address of the home agent 50 ”stored in the IPv6 address information storage unit 14 is set as the“ destination address ”. Also, the "registration request packet" is added to the "recipient option header"
“Coexistence care address (IPv6)” and “Mobile terminal 10 stored in the IPv6 address information storage unit 14
IPv6 address ”.

The transfer packet generator 18 uses the HA Ipv
4 address acquisition unit 13, mobile terminal IPv4 address acquisition unit 15, registration request packet generation unit 17, and transmission / reception unit 19
And a "registration request packet" generated by the registration request packet generation unit 17 is encapsulated in an IPv4 packet to generate a transfer packet that can be transferred in the visited network 2. . In the above IPv4 packet, HA Ipv4
The “IPv4 address of the home agent 50” acquired by the address acquisition unit 13 is set as the “destination address”, and the “IPv4 address of the mobile terminal 10” acquired by the mobile terminal IPv4 address acquisition unit 15 is set as the “source address”. By doing so, the encapsulation described above is performed.

The transmission / reception unit 19 includes a transfer packet generation unit 18
The transfer packet generated by the transfer packet generation unit 18 is transmitted to the visited network 2 by using the route control information for the IPv4 protocol. Further, the transmission / reception unit 19 transmits the I transmitted from the visited network 2 by the route control information for IPv4 protocol.
It receives a Pv4 packet.

The network relay device 30 is composed of, for example, one or a plurality of routers arranged between the home network 1 and the visited network 2, and has a basic TCP / IP communication path control function. ,
It has a DNS server function and a NAT conversion function. Specifically, the network relay device 30, as shown in FIG. 3, has a registration request packet determination unit 31, a NAT conversion function 32, an IPv6 address generation unit 33, a transfer packet generation unit 34, and an address conversion table storage. Part 35
And a transmission / reception unit 36 and a DNS function unit 37.

The registration request packet judgment unit 31 is connected to the NAT conversion function 32 and the IPv6 address generation unit 33, and examines the IPv4 header of the IPv4 packet received from the visited network 2 to check this I
It is to judge whether the content encapsulated in the Pv4 packet is a “registration request packet”.

The NAT conversion function 32 is connected to the registration request packet determination unit 31, the transfer packet generation unit 34, and the address conversion table storage unit 35, and the registration request packet determination unit 31 determines the contents of the above-mentioned IPv4 packet. When it is determined that the packet is not the “registration request packet”, the IPv4 address set in the IPv4 header in the IPv4 packet is set based on the address translation table 35a stored in the address translation table storage unit 35.
It is an address conversion means for converting an IPv6 address.

The IPv6 address generation unit 33 is connected to the registration request packet determination unit 31, the transfer packet generation unit 34, and the address conversion table storage unit 35. IPv6
The 6-address generation unit 33 uses the registration request packet determination unit 31
When it is determined that the content of the IPv4 packet is a "registration request packet", the "destination address" set in the IPv4 header of the IPv4 packet is determined.
That is, the "IPv4 address of the home agent 50" is converted into the "IPv6 address of the home agent 50" based on the address conversion table 35a stored in the address conversion table storage unit 35. Further, the IPv6 address generation unit 33 uses the IPv4
By adding a predetermined prefix to the “source address” set in the IPv4 header in the packet, that is, the “IPv4 address of the mobile terminal 10,” the “IPv6 address of the mobile terminal 10 (coexistence care address (IP
v6), mapped address (IPv6)) ".

The transfer packet generation unit 34 is connected to the NAT address conversion unit 32, the IPv6 address generation unit 33, and the address conversion table storage unit 35, and the IPv6
Is used to generate a transfer packet that can be transferred in the home network 1 using IPv4 or the visited network 2 using IPv4.

When the network relay device 30 receives the IPv4 packet encapsulating the “registration request packet” from the visited network 2, the transfer packet generating unit 34 causes the IPv6 address generating unit 33 to store the address in the address conversion table storage unit 35. The “IPv6 address of the home agent 50” converted based on the stored address conversion table 35a is set as the “destination address”, and I
By setting the “coexistence care-of address (IPv6)” generated by the Pv6 address generation unit 33 as the “source address”, a transfer packet conforming to IPv6 is generated.

When the network relay device 30 receives an IPv4 packet in which the “registration request packet” is not encapsulated from the visited network 2, the transfer packet generator 34 causes the NAT address converter 32 to store the address conversion table. The IPv6 address converted based on the address conversion table 35a stored in the unit 35 is used to generate a transfer packet conforming to IPv6.

Further, when the network relay device 30 receives the IPv6 packet from the home network 1, the transfer packet generation unit 34 has the address conversion table 35 stored in the address conversion table storage unit 35.
Using the IPv4 address translated based on a
It is an address conversion unit that generates a v4 compliant transfer packet. However, I received from home network 1
When the destination address of the Pv6 packet is the “coexistence care-of address (IPv6)” including a predetermined prefix, the transfer packet generation unit 34 uses this destination address in a predetermined method (for example, a predetermined prefix This is a destination address conversion means for changing to an IPv4 address by the method of deleting).

The address conversion table storage unit 35 stores the NA
It is connected to the T address conversion unit 32, the IPv6 address generation unit 33, the transfer packet generation unit 34, and the DNS function unit 37, and stores the address conversion table 35a.

As shown in FIG. 4, the address conversion table 35a includes, for example, "host name (option)" and "IP
The “v4 address (32 bits)” and the “IPv6 address (128 bits)” are associated with each other. The address conversion table 35a is registered by the DNS function unit 37 and associates the "IPv6 address of the mobile terminal 10" with the "IPv4 address of the mobile terminal 10".

The transmission / reception unit 36 includes a transfer packet generation unit 34.
Connected to the home network 1 according to the route control information for the IPv6 protocol, and transmits the transfer packet generated by the transfer packet generation unit 34 to the IPv4.
It is transmitted to the visited network 2 according to the protocol route control information.

The DNS function unit 37 is connected to the address conversion table storage unit 35, is composed of an IPv6 protocol DNS server and an IPv4 protocol DNS server, and responds to an inquiry including a host name with an IPv6 address or It provides an IPv4 address. The DNS function unit 37 is the H of the mobile terminal 10.
A “IPv6 address of home agent 50” is acquired in response to an inquiry from the IPv4 address acquisition unit 13. Then, the DNS function unit 37 assigns the “IPv4 address of the home agent 50” to the acquired “IPv6 address of the home agent 50”, associates the IPv6 address with the IPv4 address, and registers the address in the address translation table 35a. The associating means provides the registered "IPv4 address of home agent 50".

The home agent 50 is arranged in the home network 1 and registers address information relating to the mobile terminal 10. The home agent 50 is composed of, for example, a router. The home agent 50, when the mobile terminal 10 is away from the home network 1 and exists in the visited network 2, sends a packet addressed to the mobile terminal 10 to the network based on the address information of the registered mobile terminal 10. Transfer to the relay device 30.

The visited agent 51 is arranged in the visited network 2 and provides the mobile terminal 10 existing in the visited network 2 with a connection point to the IP network. The visited agent 51 is composed of, for example, a router.

The DHCP server 52 is arranged in the visited network 2 and allocates an IPv4 address to the mobile terminal 10 existing in the visited network 2 according to the DHCP protocol.

The radio relay device 53 is a radio base station for performing radio communication with the mobile terminal 10, a radio control device for controlling the radio base station, and an exchange for exchanging data transmitted from the mobile terminal. And a device. The wireless relay device 53 is installed in both the home network 1 and the visited network 2.

(Operation of Mobile IP Communication System According to this Embodiment) A mobile IP communication method using the mobile IP communication system having the above configuration can be implemented by the following procedure. FIG. 5 is a time chart showing the operation when the mobile terminal 10 moves from the home network 1 to the visited network 2 in the mobile IP communication system according to this embodiment.

As shown in FIG. 5, in step A1, the movement detection unit 11 of the mobile terminal 10 detects that it has moved to the visited network 2 from the router advertisement message of ICMP. Then, the mobile terminal IPv4 address acquisition unit 15 of the mobile terminal 10 makes the DHCP server 52
To the wireless relay device 53, a wireless signal requesting that the mobile terminal 10 be assigned an IPv4 address. In step A2, the wireless relay device 53 transfers the wireless signal described above to the DHCP server 52.

In step A3, the DHCP server 5
2 is the IPv4 assigned to the mobile terminal 10.
The address is transmitted to the wireless relay device 53. Step A4
In the wireless relay device 53, the mobile terminal 1
"IPv4 address of 0" is transferred to the mobile terminal 10, and the mobile terminal IPv4 address acquisition unit 15 of the mobile terminal 10 acquires the above-mentioned "IPv4 address of the mobile terminal 10."

In step A5, the protocol detection unit 12 of the mobile terminal 10 determines that the visited network 2 is "I".
Pv4 ”is used, the mobile terminal 10
The HA IPv4 address acquisition unit 13 uses the “host name of the home agent 50” stored in the IPv6 address information storage unit 14 to wirelessly relay a wireless signal for inquiring about the “IPv4 address of the home agent 50”. It is transmitted to the device 53. In step A6, the wireless relay device 53 transfers the above-described wireless signal to the network relay device 30.

In step A7, the DNS function unit 37 of the network relay device 30 determines the "home agent 50" based on the "host name of the home agent 50".
Of the IPv6 address ”, the IPv4 address is assigned to the IPv6 address, and the IPv6 address and the IPv4 address are associated and registered in the address translation table 35a.

In step A8, the DNS function unit 37 of the network relay device 30 transfers the retrieved "IPv4 address of the home agent 50" to the wireless relay device 53, and in step A9, the wireless relay device 5
3 is "IPv4 address of home agent 50"
Is transferred to the mobile terminal 10 via a wireless channel.

At step A10, the mobile terminal 10
The transfer packet generation unit 18 of the IPv6 transfers the “registration request packet” generated by the registration request packet generation unit 17 to the IPv6.
By encapsulating in 4 packets, a transfer packet that can be transferred in the visited network 2 is generated.
Then, the transmission / reception unit 19 of the mobile terminal 10 transmits this transfer packet to the wireless relay device 53 via the wireless channel.

FIG. 6A shows a transfer packet generated by the transfer packet generator 18 of the mobile terminal 10.
This transfer packet is composed of an IPv4 header having routing control information for IPv4 protocol, an IPv6 header of the encapsulated “registration request packet”, an authentication header, and a receiver option header.

This transfer packet has the "IPv4 address of the mobile terminal 10 (second IP address of the mobile terminal 10)" acquired by the mobile terminal IPv4 address acquisition unit 15 as the "source address" in the IPv4 header. ", And HA IPv6 as the" destination address "
The IPv4 address of the home agent 50 (the home agent 5
0 second IP address) ". In addition, this transfer packet includes, in the IPv6 header, the “IPv6 address of the mobile terminal 10 (mobile terminal IPv6 address A, mobile terminal 10 of the mobile terminal 10 generated by the mobile terminal IPv6 address generation unit 16 as“ source address ”). The third IP address) ”is set and the“ destination address ”is set to the“ IPv6 address of the home agent 50 (first IP address of the home agent 50) ”stored in the IPv6 address information storage unit 14. Further, this transfer packet includes the "mobile terminal IPv6 address generation unit 1" in the receiver option header.
“IPv6 address of the mobile terminal 10 (mobile terminal IPv6 address A, third IP address of the mobile terminal 10)” generated by No. 6 and the “mobile terminal stored in the IPv6 address information storage unit 14. 10 IPv6 addresses (mobile terminal IPv6 address B, mobile terminal 1
0 first IP address) ”.

In step A11, the wireless relay device 5
3 transfers the transfer packet to the visited agent 51, and in step A12, the visited agent 51
Transfers the transfer packet to the network relay device 30.

In step A13, the transfer packet generator 34 of the network relay device 30 generates a transfer packet conforming to IPv6 based on the transfer packet conforming to IPv4 received from the home network 1.

FIG. 6B shows the network relay device 30.
The transfer packet generated by the transfer packet generation unit 34 of FIG. This transfer packet is composed of an IPv6 header having routing control information for IPv6 protocol, an IPv6 header of the encapsulated "registration request packet", an authentication header, and a receiver option header.

This transfer packet is the IP of the transfer packet.
In the v6 header, the IPv6 address generation / acquisition unit 33 of the network relay device 30 as the “source address”
The IPv6 address of the mobile terminal 10 (the mobile terminal IPv6 address A, the third IP address of the mobile terminal 10) generated by the above is set, and the IPv6 address generation acquisition of the network relay device 30 is obtained as the "destination address". The "IPv6 address of the home agent 50 (first IP address of the home agent 50)" converted by the unit 33 based on the address conversion table 35a stored in the address conversion table storage unit 35 is set. The IPv6 header, the authentication header, and the receiver option header of the “registration request packet” are the same as those of the transfer packet of FIG.

In step A14, the transmission / reception unit 36 of the network relay device 30 transmits the IPv6 compliant transfer packet to the home agent 50.

In step A15, the home agent 50 has the "mobile terminal IPv6 address A" and the "mobile terminal IPv6 address A" set in the receiver option header in the transfer packet received from the network relay device 3.
6 address B ”, the current address information of the mobile terminal 10 is registered, a“ registration response packet ”for notifying the result is generated and transmitted to the network relay device 30.

FIG. 7A shows a transfer packet for transferring the "registration response packet" generated by the home agent 50. This transfer packet includes an IPv6 header having routing control information for IPv6 protocol,
It is composed of the IPv6 header of the “registration response packet”, the authentication header, and the recipient option header.

This transfer packet is the IP of the transfer packet.
In the v6 header, "IPv6 address of home agent 50 (first IP address of home agent 50)" is set as the "source address" and "movement" that is set in the "registration request packet" as the "destination address". The IPv6 address A of the mobile terminal (the third IP address of the mobile terminal 10) is set, and this transfer packet has "Home Agent 5" as the "source address" in the IPv6 header of the "registration response packet".
0 IPv6 address (first of the home agent 50
IP address) ”, and the“ mobile terminal I ”set in the“ registration request packet ”as the“ destination address ”is set.
Pv6 address A (third IP address of mobile terminal 10) "is set. Further, this transfer packet sets "mobile terminal IPv6 address B (first IP address of mobile terminal 10)" in the receiver option header.

In step A16, the transfer packet generator 34 of the network relay device 30 converts the “source address” and the “destination address” in the “IPv6 header of the transfer packet” in the transfer packet received from the home agent 50. , IPv4 compliant transfer packet is generated.

FIG. 7B shows the network relay device 30.
The transfer packet generated by the transfer packet generation unit 34 of FIG. This transfer packet is composed of an IPv6 header having routing control information for IPv6 protocol, an IPv6 header of a "registration response packet", an authentication header, and a receiver option header.

This transfer packet is the IP of the transfer packet.
In the v4 header, the transfer packet generation unit 34 sets the address conversion table storage unit 3 as the “source address”.
The "IPv4 address of the home agent 50 (second IP address of the home agent 50)" converted based on the address conversion table 35a of No. 5 is set,
"The IPv4 address of the mobile terminal 10 (the second IP address of the mobile terminal 10) converted as a" destination address "by the transfer packet generation unit 34 by a predetermined method (for example, a method of deleting a predetermined prefix) Is set. The IPv6 header, the authentication header, and the receiver option header of the “registration response packet” are the same as those of the transfer packet of FIG. 7A.

In step A17, the transmission / reception unit 36 of the network relay device 30 transmits the generated transfer packet to the visited agent 51, and in step A18, the visited agent 51 transmits this transfer packet to the wireless relay device 53. Then, in step A19, the wireless relay device 53 transfers the transfer packet to the mobile terminal 10 via the wireless channel. Then, the transmission / reception unit 19 of the mobile terminal 10 receives this transfer packet and confirms that the contents include the "registration response packet". Through the above steps, the current address information of the mobile terminal 10 that has moved to the visited network 2 is registered in the home agent 1.

In step B1, the IP packet addressed to the mobile terminal 10 after the above-mentioned registration is encapsulated into a transfer packet by the home agent 50,
It is transferred to the network relay device 30.

FIG. 8A shows a transfer packet encapsulated by the home agent 50. This transfer packet is composed of an IPv6 header having routing control information for IPv6 protocol, an IPv6 header of “IP packet addressed to mobile terminal 10”, and a payload.

This transfer packet is the IP of the transfer packet.
In the v6 header, "IPv6 address of home agent 50 (first IP address of home agent 50)" is set as "source address", and "mobile terminal registered in home agent 50 as" destination address ". IPv6 address A (mobile terminal 10
Third IP address) ”. In addition, this transfer packet is I of “IP packet addressed to mobile terminal 10”.
In the Pv6 header, as the “source address”, “IPv6 address of the source terminal (first IP of the source terminal
Address) ”and registered as the“ destination address ”in the home agent 50 to the“ mobile terminal IPv4 ”.
6 address B (first IP address of mobile terminal 10) "is set.

In step B2, the transfer packet generator 34 of the network relay device 30 converts the "source address" and "destination address" in the "IPv6 header of the transfer packet" in the transfer packet packet received from the home agent 50. Then, a transfer packet conforming to IPv4 is generated.

FIG. 8B shows the network relay device 30.
The transfer packet generated by the transfer packet generation unit 34 of FIG. This transfer packet is composed of an IPv4 header having routing control information for IPv4 protocol, an IPv6 header of "IP packet addressed to mobile terminal 10", and a payload.

This transfer packet is the IP of the transfer packet.
In the v4 header, the transfer packet generation unit 34 sets the address conversion table storage unit 3 as the “source address”.
5, the "IPv4 address of the home agent 50 (the second IP address of the home agent 50)" converted based on the address conversion table 35a stored in 5 is set, and predetermined by the transfer packet generation unit 34 as the "destination address". The "IPv4 address of the mobile terminal 10 (second IP address of the mobile terminal 10)" converted by the method (for example, a method of deleting a predetermined prefix) is set. The IPv6 header and payload of the “IP packet addressed to mobile terminal 10” are the same as those of the transfer packet of FIG. 8A.

In step B3, the transmission / reception unit 36 of the network relay device 30 sends the transfer packet generated by the transfer packet generation unit 34 to the visited agent 5
Send to 1. In step B4, the visited agent 51 transfers the above transfer packet to the wireless relay device 53, and the wireless relay device 53 transfers the above transfer packet to the mobile terminal 10 via the wireless channel. Then, the transmission / reception unit 19 of the mobile terminal 10 receives the above-mentioned transfer packet, and in the contents thereof, "IP addressed to the mobile terminal 10" is received.
Packet is included.

(Operation / Effect of Mobile IP Communication System According to this Embodiment) According to the mobile IP communication system and mobile IP communication method according to this embodiment, the DNS function unit 37 of the network relay device 30 has the second function. “DNS about IPv4 address of home agent 50” received from mobile terminal 10 via network 2.
In response to "inquiry", "IP of home agent 50"
v6 address "and" IPv4 of home agent 50 "
Address translation table 35a in association with "address"
IP network 1 using IPv6 for storage in
It is possible to convert the IP address of the home agent 50 between the IP address and the IP network 2 using IPv4.

Further, according to the mobile IP communication system and the mobile IP communication method according to the present embodiment, the IPv6 address generation unit 33 of the network relay device 30 causes the I in the registration request packet transmitted by the mobile terminal 10.
The source address in the P route control information is converted into a “coexistence care address of mobile terminal (IPv6)”, and the home agent 50 registers this “coexistence care address of mobile terminal (IPv6)”. The transfer packet generation unit 18 of the network relay device 50 displays the “mobile terminal 10
By deleting a predetermined prefix from the "coexistence care of address (IPv6) of"
Since it is possible to generate a "v4 address", IPv6
It is possible to maintain the continuity of mobile IP communication even in an environment in which the IP network 1 using IPv4 and the IP network 2 using IPv4 coexist.

[0072]

As described above, according to the present invention, it is possible to perform "mobile IP communication" in an environment in which IP networks using a plurality of versions of IP protocols are mixed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a mobile IP communication system according to an embodiment of the present invention.

FIG. 2 is a block diagram showing schematic functions of a mobile terminal according to an embodiment of the present invention.

FIG. 3 is a block diagram showing a schematic function of a network relay device according to an embodiment of the present invention.

FIG. 4 is a block diagram showing an address conversion table according to an embodiment of the present invention.

FIG. 5 is a time chart diagram showing an operation when a mobile terminal moves from a home network to a visited network in the mobile IP communication system according to the embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a transfer packet for transferring a registration request packet in the mobile IP communication system according to the embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a transfer packet for transferring a registration response packet in the mobile IP communication system according to the embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a transfer packet for transferring an IP packet in the mobile IP communication system according to the embodiment of the present invention.

[Explanation of symbols]

1 ... Home network 2 ... Visited network 10 ... Mobile terminal 11 ... Movement detection unit 12 ... Protocol detection unit 13 ... HA IPv4 address acquisition unit 14 ... IPv6 address information storage unit 15 ... Mobile terminal IPv4 address acquisition unit 16 ... Mobile terminal IPv6 address generation unit 17 ... Registration request packet generator 18 ... Transfer packet generator 19, 36 ... Transceiver 30 ... Network relay device 31 ... Registration request packet determination unit 32 ... NAT address converter 33 ... IPv6 address generator 34 ... Transfer packet generator 35 ... Address conversion table storage unit 35a ... Address conversion table 37 ... DNS function unit 50 ... Home Agent 51 ... Visited agent 52 ... DHCP server 53 ... Wireless relay device

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5K030 GA08 HA08 HC01 HC09 HD09                       JL01 KA04 KA05 MD09                 5K067 AA22 BB04 BB21 DD17 EE02                       EE10 EE16 HH05 HH22 HH23

Claims (9)

[Claims] 1. A mobile terminal, a home agent for managing a first IP address of the mobile terminal allocated in a first network, and a second network which is the first network and another network. A mobile IP communication system comprising: a network relay device for connecting a network, wherein the network relay device comprises a first IP address assigned in the first network and a second IP address assigned in the second network. An address translation table that stores the IP address of the home agent in association with the second address of the home agent in response to an inquiry about the second IP address of the home agent received from the mobile terminal via the second network. IP address of 1 and the home agent 2nd
And an address in an IP packet transmitted / received between the first network and the second network based on the address conversion table. A mobile IP communication system comprising: 2. A mobile terminal, a home agent for managing a first IP address of the mobile terminal allocated in the first network, and a second network which is the first network and another network. A mobile IP communication system comprising: a network relay device for connecting a first IP address assigned to the first network, the first address system assigned to the first IP address assigned to the first network, and a second address assigned to the second network. Unlike the second address system of two IP addresses, the mobile terminal is configured to convert the second IP address of the mobile terminal so as to comply with the first address system and the third IP of the mobile terminal. Registration request packet for generating a registration request packet for registering an address with the home agent The registration request packet is encapsulated and transmitted by the generation means and the IP routing control information having the second IP address of the mobile terminal as a source address and the second IP address of the home agent as a destination address. Registration request packet transmitting means, wherein the network relay device complies with the source address in the IP route control information in the registration request packet transmitted by the mobile terminal according to the first address system. A mobile IP communication system comprising a source address translation means for translating into a third IP address of a mobile terminal. 3. The registration request packet generation means assigns a second prefix to the second IP address of the mobile terminal to give a third IP address of the mobile terminal.
The address is converted into an address, and the transmission source address conversion means converts the transmission source address into a third IP address of the mobile terminal by adding a predetermined prefix. Mobile IP communication system as described. 4. The network relay device comprises the first
The destination address of the IP packet addressed to the third IP address of the mobile terminal, which is supplied from the network, and converts the selected destination address of the IP packet into the second IP address of the mobile terminal. The mobile IP communication system according to claim 2, further comprising a destination address conversion unit. 5. A mobile terminal, a home agent for managing a first IP address of the mobile terminal assigned in the first network, and a second network which is the first network and another network. A mobile IP communication method performed by a network relay device for connecting a network, wherein in the network relay device, a first IP address assigned in the first network and a second IP address assigned in the second network. I
In response to an inquiry about the second IP address of the home agent received from the mobile terminal via the second network, an address conversion table storing the P address in association with the first of the home agent Storing the IP address of the home agent and the second IP address of the home agent in association with each other, between the first network and the second network in the network relay device based on the address conversion table. And a step of converting an address in an IP packet transmitted and received by the mobile IP communication method. 6. A mobile terminal, a home agent managing a first IP address of the mobile terminal allocated in the first network, and a second network which is the first network and another network. A mobile IP communication method performed by a network relay device that connects a second network, wherein a first address system of a first IP address assigned in the first network is a second address system assigned in the second network. The second IP address of the mobile terminal is different from the second address system of the IP address of the mobile terminal.
Generating a registration request packet for registering a third IP address of the mobile terminal whose address has been converted to comply with the first address system with the home agent; Second IP of terminal
A step of encapsulating and transmitting the registration request packet by IP route control information having an address as a source address and a second IP address of the home agent as a destination address; and the mobile terminal in the network relay device. Converting the source address in the IP route control information in the registration request packet transmitted by the above into a third IP address of the mobile terminal according to the first address system. Mobile I
P communication method. 7. In a mobile IP communication system, a network relay device for connecting a first network including a home agent and a second network which is another network, the network relay device being assigned in the first network. An address translation table that stores the first IP address and the second IP address assigned in the second network in association with each other; and the second of the home agents received from the mobile terminal via the second network. In response to an inquiry about the IP address of the home agent and the second I of the home agent.
An address associating unit that associates a P address with each other and stores it in the address translation table, and an address in an IP packet transmitted and received between the first network and the second network based on the address translation table. A network relay device comprising: an address translation unit for translating. 8. A mobile station in a mobile IP communication system, which is a network relay device for connecting a first network including a home agent and a second network which is another network, the network relay device being assigned in the first network. The first address system of one IP address is different from the second address system of the second IP address assigned in the second network, and the second IP address of the mobile terminal is changed to the first address system. Third IP of the mobile terminal converted to comply with the scheme
Source address translation means for translating the source address in the IP route control information in the registration request packet for registering an address into the home agent into the third IP address of the mobile terminal according to the first address system. A network relay device comprising: 9. A mobile terminal used in mobile IP communication, which is a first IP assigned in a first network.
The first address system of the address is different from the second address system of the second IP address assigned in the second network, and the second IP address of the mobile terminal follows the first address system. Registration request packet generation means for generating a registration request packet for registering the converted third IP address of the mobile terminal in a home agent; and a second IP address of the mobile terminal as a source address, A mobile terminal, comprising: a registration request packet transmitting means for encapsulating and transmitting the registration request packet by IP route control information having the second IP address of the home agent as a destination address.