JP3339514B2 - Mobility management device, packet relay device, and mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a mobile computer in which an address is assigned to each network as the mobile computer moves between networks, and communicates continuously before and after the mobile computer.
A mobility management device for managing addresses of mobile computers,
The present invention relates to a packet relay device that relays a packet and a communication system having the same.

[0002]

2. Description of the Related Art In recent years, personal computers and workstations have been reduced in size and weight, and techniques for supporting portable machines have been required.
In this type of computer, it is conceivable that the computer is once disconnected from the connected network and then connected to the network again at the destination and used.

A computer (hereinafter, referred to as a node) connected to a network is assigned an address for specifying the node. Usually, this address includes position information indicating the network to which the address belongs, so that it is necessary to perform communication using an address corresponding to the destination each time the user moves. For example, when an address is composed of a network part for specifying a network and a node part for specifying an individual node in the network, the address changes every time the mobile terminal moves between networks. For example, the conventional INTERNET PROTOCO
L (Reference: Jon Postel, INTERNET PROTOCOL, RFC791, S
ep., 1981), the address itself includes location information, so that a moved node is assigned a different address each time it moves.

In a network having such a moving node, when another node that has been communicating before the movement transmits a packet to the address before the movement, the packet is no longer stored at the position indicated by the address before the movement. Since the moved node does not exist, it is discarded. Then, the communication before the movement cannot be continued due to the movement. This is because many communication control methods used in personal computers and workstations do not assume that the computer of the communication partner moves.

Conventionally, assuming that a computer of a communication partner moves, for example, Japanese Patent Application No. 1-2315 is disclosed.
No. 38 describes a frame transfer method. However, in this frame transfer method, the destination address is directly changed from the address before movement to the address after movement,
It was not possible to communicate continuously before and after moving. In addition, as a node position transparent communication method for performing continuous communication even when a communication partner moves, an approach of VIP (Virtual IP Protocol) of Sony Computer Science Laboratories Inc. (Reference: "VIP: Virtual Internet Protocol") "Fumio Teraoka, Yasuhiko Yokote, Mario Tokoro, IPSJ SIG Report, Multimedia Communication and Distributed Processing, 1991, 7, 5) have been proposed. In this VIP approach, a gateway that relays a packet transmits a packet in which address information after movement is added to a packet addressed to an address before movement to the address after movement. For this reason, the mobile node can know the correspondence between the address before movement and the address after movement, and can perform continuous communication before and after movement.

A node position transparent communication system in the conventional VIP approach will be described with reference to FIG. In this method, the mobile node 33 has a virtual network address and a physical network address. The virtual network address is an address that does not change even if it moves, and is used as a source / destination address by a communication application on the mobile node. The physical network address is an address that changes with movement and indicates a physical location. The above two addresses assigned to the mobile node 33 are held by the gateway 32 connected to the network to which the virtual network address belongs.

[0007] The general node 31, which is the communication partner of the mobile node 33, transmits a packet (pre-relay packet 34) addressed to the virtual network address to the mobile node 33. The format of the pre-relay packet 34 is shown in FIG.
(A). In the figure, α is the virtual network address of the mobile node 33 before moving, and r is the physical network address of the general node 31.

The pre-relay packet 34 is converted into a packet addressed to the physical network address (post-relay packet 35) when passing through the gateway 32. That is, when the gateway 32 receives the pre-relay packet 34, the gateway 32 refers to the cache in which the correspondence between the virtual network address and the physical network address is entered, and converts the packet into the post-relay packet 35 addressed to the physical network address. Send out. This post-relay packet 3
5 is shown in FIG. In the figure,
β is information after the physical network address after the movement and a protocol header portion added by the gateway 32.

Since the post-relay packet 35 is addressed to the physical network address, if there is a gateway on the route, it arrives at the mobile node 33 via the gateway. In this way, the post-relay packet 35 is
And is restored to the original pre-relay packet 34 before moving. Upon relaying, upon receiving the post-relay packet 35, the gateway located on the route obtains the correspondence between the virtual network address and the physical network address of the mobile node from the protocol header when controlling the route of the packet. The correspondence between the obtained virtual network address and physical network address is held as a cache. As a result, the gateway can keep the latest address. When a response packet is returned from the mobile node 33 to the general node 31, the physical network address of the mobile node 33 and the virtual network address are propagated to the general node 31.

[0010] As described above, in the VIP system, the mobile node and the application of the partner node can communicate using the same virtual network address. That is, the mobile node 33 can receive the pre-relay packet 34 addressed to the same address virtual network before and after the movement, and can communicate continuously before and after the movement. However, it is necessary that the general node 31 and the gateway 32 can interpret the virtual network address.

[0011]

However, according to the above-described prior art node location transmission scheme, all nodes on the network that want to communicate with the mobile node must be connected to the virtual VI.
Since it is necessary to extend the function so that the P address can be interpreted, there is a problem that all the existing nodes must be modified.

In other words, changing the gateway of an already operated network has a large operational risk, and is often a dedicated machine designed by a manufacturer in many cases. In practice, it is extremely difficult to expand the network. . Further, some of the general nodes 31 that communicate with the mobile node 33 also have an operating system unique to the manufacturer, and there is a problem that it is difficult to expand all the general nodes.

In view of the above problems, the present invention manages the addresses of mobile computers to which a mobile computer to which an address is assigned for each network as it moves between networks can communicate continuously before and after the movement. It is an object of the present invention to provide a mobility management device, a packet relay device for relaying a packet, and a communication system having the same.

[0014]

In order to achieve the above object, a mobility management apparatus according to the present invention is provided on a mobile node having a home address that does not change even when it moves, and is connected between the mobile node and a network. Address management means for managing addresses of packets to be transmitted / received by a mobile node, the address holding means holding a home address of the mobile node and a current temporary address assigned to each destination of movement between networks; Packet receiving means for receiving a packet having a destination address of a packet input from the same address as the temporary address held in the address holding means, and a destination address set for the packet received by the packet receiving means. Rewrites the temporary address to the home address and adds the source address to the packet Address restoring means for rewriting to the address of the communication partner based on the received information and passing it to the mobile node, and for the packet to be transmitted from the mobile node, the home address set as the source address as the temporary address, the destination address Address translation means for rewriting the address of the communication partner set as the address of the packet relay device connected to the network to which the home address belongs, and adding the address of the communication partner as additional information.

[0015] The mobility management device may further include a temporary address management means for acquiring a temporary address from a server device for managing an address on the network when writing, and writing the acquired temporary address in the address holding means. Further, the packet relay device of the present invention is a packet relay device for relaying communication between a mobile node having a home address that does not change even when it moves and a communication partner node that is a communication partner of the mobile node. Address set holding means for holding the home address of a mobile node having a home address in the network to which the device is connected, and the temporary address assigned at the destination of the movement in association with the movement between the networks; Packet receiving means for receiving, from a network, a packet whose destination address of the packet to be transmitted matches the home address held in the address set holding means, and a packet addressed to the address of the packet relay apparatus, and Sent for received packet addressed to home address The address of the communication partner of the mobile node set as the address is rewritten to the address of the packet relay device itself, the home address of the mobile node set as the destination address is rewritten to the current temporary address, and the original source address is added information. A temporary address of a mobile node set as a source address for a home address and a destination address for a packet addressed to its own address received by a relay packet receiving unit. And a relay address restoring means for rewriting the address of the packet relay apparatus itself to the address of a general host included in the additional information.

[0016] The packet relay apparatus may further include address correspondence obtaining means for receiving a packet containing the correspondence between the home address and the temporary address and writing the received packet into the address set holding means. Further, a communication system of the present invention includes a mobile node having the mobility management device and the packet relay device.

In the communication system, in the mobility management device, the temporary address management means, upon acquiring the temporary address, transmits a packet including a correspondence between the temporary address and the home address after the movement of the mobile node. A control packet including information indicating whether to start or end and a home address of the mobile node is transmitted, and in the packet relay device, the address set holding unit associates the address with the set of the home address and the temporary address, and Holding a flag indicating whether or not to relay the packet having, the address correspondence obtaining means sets the flag of the address set holding means based on the control packet transmitted from the mobile node, and the relay packet receiving means When the flag indicates that the packet is not relayed, the packet is not received. It may be.

[0018]

According to the above means, in the mobility management apparatus of the present invention, the packet receiving means receives a packet in which the destination address of the packet input from the network matches the temporary address held in the address holding means. In the received packet, the temporary address set as the destination address is rewritten to the home address by the address restoring unit, and the source address is rewritten to the address of the communication partner based on the information added to the packet. Passed to. In the packet to be transmitted from the mobile node, the home address set as the source address is connected to the temporary address, and the address of the communication partner set as the destination address is connected to the network to which the home address belongs by the address conversion means. The address of the packet relay device is rewritten, and the address of the communication partner is added as additional information.

In addition, the temporary address management means of the mobility management device acquires a temporary address from a server device that manages addresses on the network when moving, and writes the temporary address in the address holding means. In the packet relay device of the present invention, the relay packet receiving means is configured to output a packet whose destination address of the packet input from the network matches the home address held in the address set holding means, and a packet addressed to the address of the packet relay device. Receive packets from the network. In the packet addressed to the home address received by the relay packet receiving means, the address of the communication partner of the mobile node set as the source address is rewritten to the address of the packet relay apparatus itself by the relay address conversion means, and the destination address is set as the destination address. The set home address of the mobile node is rewritten to the current temporary address, and the original source address is added as additional information. The packet addressed to the address of the packet relay device received by the relay packet receiving unit is a packet in which the temporary address of the mobile node set as the source address is set to the home address and the destination address is set by the relay address restoring unit. The address of the relay device itself is rewritten to the address of the general host included in the additional information.

Further, in the packet relay device, the address correspondence obtaining means receives the packet including the correspondence between the home address and the temporary address and writes the packet in the address set holding means. In the communication system of the present invention, a mobile node having a mobility management device transmits and receives packets to and from another node via a packet relay device.

In the communication system, the control packet transmitted from the temporary address management means of the mobility management device is received by the address correspondence obtaining means in the packet relay device. The address correspondence obtaining means sets the flag of the address set holding means based on the control packet. The relay packet receiving means controls the operation according to the value of the flag.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mobile communication device according to the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
1 is a diagram showing a configuration of a mobile communication device (hereinafter, referred to as a packet relay device). The packet relay device 10 includes a relay packet receiving unit 1, an address converting unit 2, an address restoring unit 3,
An address set holding unit 4 and an address correspondence obtaining unit 5 are provided, and are connected to a network via a line control unit 7.

The relay packet receiving unit 1 receives a packet to be relayed from the packets input from the network via the line control unit 7 with reference to the address set holding unit 4. The relay packet receiving unit 1 captures a packet to be relayed, for example, by using a NIT provided by SunOS.
This can be done through the interface. The address translator 2 translates an address of a packet addressed to a mobile node from a general node in a packet received by the relay packet receiver 1. Specifically, the source address in the packet is rewritten from the address of the general node to the address of the packet relay device 10 itself, and the destination address is rewritten from the home address of the mobile node before moving to the temporary address after moving, The original transmission source address is set as additional information. Note that the home address of the mobile node is an address before movement in the first movement after the start of communication, and the temporary address of the mobile node is an address at a newly assigned destination.

The address restoring unit 3 converts an address of a packet addressed to a general node from a mobile node among the packets received by the relay packet receiving unit 1. In particular,
The source address is rewritten from the temporary address after the movement of the mobile node to the home address before the movement, and the destination address is rewritten from the address of the packet relay device 10 itself to the address of the general host set as additional information.

The address set holding unit 4 manages a packet relay management table 6 for holding an address set of a home address (relay source address) and a temporary address (relay destination address) of the mobile node. Packet relay management table 6
Is a relay packet receiving unit 1 and an address correspondence obtaining unit 5
Is accessed from the address group via the address set holding unit 4, and is used by the relay packet receiving unit 1 to determine the packet to be relayed and to manage the address of the mobile node. FIG. 5 shows an example of the packet relay management table. In the figure, “relay source address” indicates the home address of the mobile node. “Relay destination address” indicates a temporary address of the mobile node. “Flag” indicates whether to relay a packet addressed to the relay source address of the entry. When this flag is on, relaying is performed when a packet addressed to the relay source address is captured, and when the flag is off, relaying is not performed even if a packet of the relay source is captured. The on / off state of this flag is set by the address correspondence obtaining unit 5.

The address correspondence acquisition unit 5 receives a control packet indicating the correspondence between the home address and the temporary address and a packet for controlling the flag from the mobile node, and writes the packet in the packet relay management table 6 in accordance with the instruction of the packet. , Do an update. FIG. 6 shows a format of a control packet transmitted from the mobile node 14. FIG.
(A) is a format when a mobile node requests to relay a packet immediately after moving, and includes a “relay source address”, a “relay destination address”, and a “flag” indicating whether to start relaying. Consists of FIG. 6 (b),
(C) is a format for instructing the start and end of the relay, respectively, and includes a “relay source address”, a “relay destination address” with a value of 0, and a “flag”.

The line controller 7 controls the connection between the packet relay device 10 and the network. FIG. 2 is a diagram illustrating a configuration of a second mobile communication device (hereinafter, referred to as a mobility management device). In FIG. 1, a mobility management device 20 on a mobile node is provided on the mobile node, and includes a relay packet receiving unit 21, an address restoring unit 22, and an address translating unit 2.
3 and a temporary address management unit 25, and are connected to a network via a line control unit 26 and to a higher-level communication control unit 27.

The relay packet receiving unit 21 determines whether or not the destination address of the packet received from the network via the line control unit 26 matches the temporary address held in the temporary address management unit 25 or its own home address. Check if. As a result, if the address matches the temporary address, the packet is passed to the address restoring unit 22, and if the address matches the home address, the packet is passed to the higher-level communication control unit 27.

The address restoring unit 22 restores the transmission destination address and the transmission source address of the packet passed from the relay packet receiving unit 21 to the original addresses when the transmission source transmitted. That is, the destination address of the packet is rewritten to its own home address, and the source address is rewritten to the original source address attached as additional information of the packet. The rewritten packet is passed to the upper communication control unit 27.

The address conversion unit 23 converts the destination address of the packet passed from the upper communication control unit 27 into the address of the packet relay device 10 for packet relay. That is, when a packet in which the source address is the home address and the destination address is the address of the general node that is the original destination is passed from the upper communication control unit 27 to the address conversion unit 23, the address conversion unit 23
Rewrites the destination address from the address of the general node to the address of the packet relay device, and rewrites the source address from the home address to the current temporary address β, and transmits the rewritten address via the line control unit 26.

The temporary address management unit 25 receives a temporary address in the destination network. This assignment can be made manually by a network administrator or by BOOTP (see "Bill Croft and John Gil
more, BOOTSTRAP PROTOCOL, RFC951, Sep., 1985 ") server and DHCP (Reference: R.Droms, Dynamic Host C)
onfigulation Protocol, Internet-Draft, July, 1991) server. FIG. 6D shows a format of a packet for transmitting a temporary address from the address management server to the mobile node when assigned by such an address management server. When receiving the packet shown in FIG. 6D, the temporary address management unit 25 holds the correspondence between the home address and the temporary address.

The line controller 26 controls a physical communication line. The upper communication control unit 27 inputs / outputs a packet to be transmitted / received notified by the application to the mobility management apparatus 20, and controls communication such as connection / disconnection of a connection and timer monitoring. FIG. 3 is an explanatory diagram of an example of a communication system including the packet relay device 10 and the mobility management device 20 described above. This communication system example includes a packet relay device 10, a gateway 12, a general node 13
And a mobile node 14.

In the figure, the packet relay device 10
It is assumed that the apparatus shown in FIG. 1 is assigned an address S. The gateway 12 connects the networks and passes packets from one network to the other. The general node 13 is the mobile node 1
4, and the address r is assigned.

It is assumed that the mobile node 14 is assigned a home address α in the network before the movement and a temporary address β in the network after the movement.
Also, A, B, C, and D in the figure indicate the flow of the packet, respectively. The packet A is a packet transmitted from the general node 13 and addressed to the home address α of the mobile node 14. FIG. 4A shows an example of the format of the packet A. This format consists of the “Ethernet header”, “I
P packet ”and“ dest. ”And“ s ”in the IP packet.
“rc.” is the source address and the destination address.

The packet B is a packet in which the address of the packet A is converted by the packet relay device 10 and is transmitted to the current temporary address β of the mobile node 14. FIG. 4B shows the format of the packet B. “Additional information” is added to this format. The packet C is a packet transmitted to the address of the packet relay device 10 when transmitting a packet from the mobile node 14 to the general node 13. FIG. 4C shows the format of the packet C.

The packet D is a packet in which the address of the packet C is converted by the packet relay device 10 and is transmitted to the address r of the general node 13. FIG. 4D shows the format of the packet D. The operation of the first mobile communication device (packet relay device) and the second mobile communication device (mobility management device) in the embodiment of the present invention configured as described above will be described. (Operation at the time of movement of the mobile node 14) In FIG. 3, the mobile node 14 is initially connected to a position indicated by a broken line and has a home address α, and then moves to a position indicated by a solid line to temporarily It is assumed that the address β has been assigned. The temporary address β is given by a control packet shown in FIG. 6D from an address management server (not shown) on the network via the line control unit 26 in accordance with an instruction from the upper communication control unit 27. This control packet is obtained and held by the temporary address management unit 25. This temporary address may be acquired before or after the transfer.

Mobile node 14 that has acquired temporary address β
FIG. 6 shows the packet relay device 10 after moving.
The control packet shown in (a) is transmitted with the flag on, and a relay is requested. This control packet is received by the address correspondence obtaining unit 5 of the packet relay device 10 and written into the packet relay management table 6 in the address set holding unit 4. As a result, as shown in FIG. 5, the correspondence between the relay source address α and the relay destination address β, and the flag “o”
n "is held in the packet relay management table 6. As a result, the packet relay apparatus 10 is ready to relay packets.

When the mobile node 14 notifies the control packet shown in FIG. 6 (a) of only the correspondence between the addresses with the flag off, the mobile node 14 transmits the control packet shown in FIG. 6 (b) and then relays it. May be requested to start. Or later,
The operation of the packet relay device 10 and the mobility management device 20 on the mobile node will be described along the flow of the packets A to D shown in FIG. (General Node 13 → Packet A) In FIG. 3, the general node 13 always transmits a packet to the home address regardless of whether the mobile node 14 has moved.
This is because the general node 13 is based on an existing device. (Packet A → Packet Relay Device → Packet B: Address Conversion) The packet A (see FIG. 4A) transmitted from the general node 13 reaches the relay packet receiving unit 1 in the packet relay device 10. The relay packet receiving unit 1 refers to the packet relay management table 6 (see FIG. 5),
The value of the “relay source address” is searched for an address that matches the destination address α of the packet A.
In this operation example, since there is a relay source address that matches the home address α of the mobile node 14, the corresponding relay destination address β is extracted. Further, the relay packet receiving unit 1 passes the packet A and the relay destination address β obtained from the packet relay management table 6 to the address conversion unit 2.

The address translator 2 rewrites the destination address of the packet A from the source address α to the destination address β, and changes the source address to the address r of the general node 13.
Is rewritten to the address S of the packet relay device 10 itself, and the address r, which is the original source address, is added as additional information. The packet whose address has been converted in this way is packet B (see FIG. 4B).
The packet B whose address has been converted is transmitted to the network via the line control unit 7. (Packet B → Mobile Node 14: Reception) The relay packet receiving unit 21 in the mobility management device on the mobile node 14
The packet B is received via the line controller 26. The relay packet receiving unit 21 determines that the transmission destination address of the packet B is
It is checked whether the address matches the temporary address β held in the temporary address management unit 25 or its own home address α. As a result of the check, if the packet matches the temporary address, the packet is passed to the address restoring unit 22. If the packet matches the home address, the packet is passed to the upper communication control unit 27. In the case of the present embodiment, the received packet B matches the temporary address,
Pass to.

The address restoring unit 22 rewrites the destination address β of the packet B to its own home address α, and rewrites the source address to the original source address r attached as additional information of the packet B. The rewritten packet is passed to the upper communication control unit 27. Thus, the application program on the mobile node can always receive the packet addressed to the home address. (Mobile node 14 → packet C: transmission) packet B
The mobile node 14 sends out a packet C (see FIG. 4C) in which the transmission destination address and the transmission source address of the received packet B are set in reverse.

More specifically, a packet in which the transmission source address is the home address α and the transmission destination address is the original transmission destination address r is passed from the upper communication control unit 27 to the address conversion unit 23. Address converter 23
Converts the transmission destination address from the address r of the general node 13 to the address S of the packet relay device 10 and the transmission source address from the home address α to the current temporary address β, and transmits them via the line control unit 26. The packet transmitted in this manner is packet C.

Thus, the application program on the mobile node can always transmit a packet with the home address as the source address. (Packet C → Packet Relay Device → Packet D: Address Recovery) Since the destination address of the packet C is the address S of the packet relay device 10, the packet relay device 1
0 is received by the relay packet receiving unit 1.

In the packet relay device 10, the relay packet receiving unit 1 extracts the source address of the packet C, and reads the "relay destination address" in the packet relay management table 6.
Search for an address that matches. In the case of the present embodiment, since a matching address β exists, the corresponding relay source address α is extracted. The relay packet receiving unit 1 passes the packet C and the relay source address α obtained from the packet relay management table 6 to the address restoring unit 3. Thereby, the address restoring unit 3 changes the transmission destination address from the address S to the address r (set as additional information).
Then, the source address is rewritten to the address α. The rewritten packet D is transmitted to the network via the line control unit 7. (Packet D → General Node 13) Since the packet D is a packet addressed to the address r of the general node 13 itself, it is received by the general node 13.

If the current temporary address is used as the transmission source at the time of transmission from the mobile node, no address conversion may be performed. In this case, since the packet destination address sent from the mobile node to the network remains the original destination address, the packet can communicate with the original communication partner without passing through the packet relay device. In this case, the relay packet receiving unit 21 of the mobile node, when receiving the packet having the transmission destination as the temporary address and having no additional information, may pass the packet to the higher-level communication control unit 27 as it is.

[0045]

As described above, according to the above-mentioned prior art node location transmission method of the present invention, all the nodes on the network that want to communicate with the mobile node have a virtual VIP.
Since the function needs to be extended so that the address can be interpreted, there is a problem that all the existing nodes must be modified.

In other words, changing the gateway of a network that has already been operated has a large operational risk, and is often a dedicated machine designed by a manufacturer in many cases, and it is extremely difficult to actually expand the network. . Further, some of the general nodes 31 that communicate with the mobile node 33 also have an operating system unique to the manufacturer, and there is a problem that it is difficult to expand all the general nodes.

In view of the above problems, the present invention can be applied to a device on an existing network for a mobile node moving between networks with a change in address, and the mobile node communicates continuously before and after the movement. It is an object of the present invention to provide a packet relay device capable of easily performing the above-mentioned operations. As described above, according to the mobile communication device of the present invention, in the mobility management device on the mobile node, the additional information is set by rewriting the destination address of the original packet to be transmitted to the address of the packet relay device, In the relay device, by rewriting not only the destination address but also the source address, there is an effect that the general node can communicate with the mobile node without extending the functions of the general node and the gateway.

Specifically, in the general node, the address change due to the movement of the mobile node can be hidden, so that the application program on the general node that operates while communicating with the mobile node is unique to the manufacturer. Has the effect that communication with the mobile node can be continued as it is. In the mobile node,
The address restoring means of the mobility management device makes it possible to restore the original packet from the relay packet and hide the address change due to its own movement from the application on the mobile node. Has the effect that it can operate continuously while communicating with other nodes before and after movement.

In addition, since all packets between the general node and the mobile node pass through the relay device, there is an effect that the traffic of the relay packet and the relay state can be grasped.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a packet relay device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a packet relay device provided in a mobile node.

FIG. 3 is an explanatory diagram of a communication system including the packet relay device in the embodiment.

FIG. 4 is a format diagram of a packet in the embodiment.

FIG. 5 is an explanatory diagram of a packet relay management table.

FIG. 6 is an explanatory diagram of a format of a control packet.

FIG. 7 is an explanatory diagram of a conventional node position transmission communication system.

FIG. 8 is an explanatory diagram of a packet format in a conventional node position transparent communication system.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 relay packet receiving unit 2 address conversion unit 3 address restoration unit 4 address group holding unit 5 address correspondence obtaining unit 6 packet relay management table 7 line control unit 10 packet relay device 12 gateway 13 general node 14 mobile node 20 mobility management device 21 relay Packet receiving unit 22 Address restoration unit 23 Address conversion unit 25 Temporary address management unit 26 Line control unit 27 Communication control unit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-5-83260 (JP, A) JP-A-4-54095 (JP, A) JP-A-4-154335 (JP, A) JP-A-2- 271738 (JP, A) JP-A-1-231538 (JP, A) JP-A-62-26339 (JP, A) JP-A-6-103199 (JP, A) JP-A-5-327720 (JP, A) JP-A-5-197642 (JP, A) JP-A-5-227161 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/00-12/66 G03F 13/00 H04Q 3/52 H04Q 11/00-11/04

Claims (6)

(57) [Claims] 1. A mobility management device which is provided on a mobile node having a home address which does not change when it moves, is connected between the mobile node and a network, and manages addresses of packets to be transmitted and received by the mobile node. Address holding means for holding a home address of a mobile node and a current temporary address assigned to each destination of movement between networks; a destination address of a packet input from the network and a temporary address held by the address holding means. Packet receiving means for receiving a packet which matches
Address restoration means for rewriting the temporary address set as the destination address to the home address, rewriting the source address to the address of the communication partner based on the information added to the packet, and passing the address to the mobile node, and transmitting from the mobile node. For the packet, the home address set as the source address is rewritten to the temporary address, and the address of the communication partner set as the destination address is rewritten to the address of the packet relay device connected to the network to which the home address belongs. And an address conversion means for adding the address as additional information. 2. The mobility management device according to claim 1, further comprising: a temporary address management unit that acquires a temporary address from a server device that manages an address on a network when writing, and writes the temporary address in an address holding unit. Item 1. The mobility management device according to Item 1. 3. A packet relay device for relaying communication between a mobile node having a home address that does not change even when moving and a communication partner node that is a communication partner of the mobile node, wherein the packet relay device is connected. Address set holding means for holding a home address of a mobile node having a home address in the network in correspondence with a temporary address assigned to each destination along with the movement between networks, and a destination of a packet input from the network. A relay packet receiving unit for receiving from the network a packet whose address matches the home address held in the address set holding unit, and a packet addressed to the address of the packet relay apparatus; and a home address received by the relay packet receiving unit. Set as source address for packets addressed to Rewritten the address of the communication partner of the set mobile node to the address of the packet relay device itself, rewrites the home address of the mobile node set as the destination address to the current temporary address, and adds the original source address as additional information. Relay address translating means; and for the packet addressed to its own address received by the relay packet receiving means, the temporary address of the mobile node set as the source address as the home address;
A packet relay device comprising: a relay address restoring unit that rewrites an address of the packet relay device itself set as a destination address to a general host address included in the additional information. 4. The packet relay apparatus according to claim 3, further comprising address correspondence obtaining means for receiving a packet including a correspondence between the home address and the temporary address and writing the received packet into the address set holding means. The packet relay device according to the above. 5. A mobile communication system comprising: a mobile node having the mobility management device according to claim 2; and a packet relay device according to claim 4. 6. The mobility management device, wherein the temporary address management means, when acquiring the temporary address, starts relaying a packet including a correspondence between the temporary address and the home address after the movement of the mobile node. A control packet including information indicating whether the mobile node is to be terminated and the home address of the mobile node. In the packet relay device, the address set holding unit has the address corresponding to the set of the home address and the temporary address. Holding a flag indicating whether or not to relay the packet, the address correspondence obtaining means sets the flag of the address set holding means based on the control packet transmitted from the mobile node, and the relay packet receiving means, When the flag indicates that the packet is not relayed, the packet is not received. 5 communication system described.