JPH0730544A - Movement management equipment, packet repeater, mobile communication system - Google Patents

Abstract

PURPOSE:To allow a general node to make communication with a mobile node by rewriting a transmission destination of a packet to be sent into an address of a packet repeater, setting additional information, and allowing the packet repeater to rewrite not only the destination address but also a sender address. CONSTITUTION:A packet A sent from a general node 13 reaches a relay packet reception section 1 in a packet repeater 10. The relay packet reception section 1 references a packet relay management table 6 to retrieve whether or not there is any address coincident with a destination address alpha of the packet A among 'relay source addresses'. In this case, there is a relay source address coincident with the home address alpha of a mobile node 14, a relay destination address beta corresponding to it is extracted. Furthermore, the relay packet reception section 1 gives the packet A and the relay destination address beta obtained by the packet relay management table 6 to an address conversion section 2. Thus, the general node makes communication with the mobile node.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention allows a mobile computer, which is assigned an address for each network according to the movement between networks, to communicate continuously before and after the movement.
A mobility management device that manages the address of the mobile computer,
The present invention relates to a packet relay device that relays a packet, and a communication system having these.

[0002]

2. Description of the Related Art In recent years, personal computers and workstations have been reduced in size and weight, and a technique for supporting a portable machine has been required.
In this type of computer, it may be considered that the computer is once disconnected from the connected network, and is reconnected to the network at the destination.

A computer (hereinafter referred to as a node) connected to a network is assigned an address for identifying it. Normally, this address includes position information indicating the network to which it belongs, so that it is necessary to communicate using an address according to the destination every time it moves. For example, when the address is composed of a network part for specifying the network and a node part for specifying individual nodes in the network, the address changes every time the network is moved. Also, for example, the conventional INTERNET PROTOCO
L (Reference: Jon Postel, INTERNET PROTOCOL, RFC791, S
In a network architecture such as ep., 1981), since the address itself contains the position information, the moved node is assigned a different address for each movement.

In a network having such a moving node, when another node communicating before the movement sends a packet to the address before the movement, the packet is no longer at the position indicated by the address before the movement. Since the moved node does not exist, it will be 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 other party will move.

[0005] Conventionally, for example, Japanese Patent Application No. 1-2315 has been proposed assuming that a computer as a communication partner moves.
There was a frame transfer method described in No. 38. However, in this frame transfer method, the destination address is directly changed from the pre-movement address to the post-movement address.
I was unable to communicate continuously before and after my move. In addition, as a node position transparent communication method for continuously communicating even if the communication partner moves, a VIP (Virtual IP Protocol) approach 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, to which a post-movement address information has been added, to a post-movement address address, to the post-movement address. Therefore, the mobile node can know the correspondence between the pre-movement address and the post-movement address, and can perform continuous communication before and after the 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 when moved, 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 due to movement and indicates a physical position. The 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.

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 this pre-relay packet 34 is shown in FIG.
It shows in (a). In the figure, α is the virtual network address of the mobile node 33 before the movement, and r is the physical network address of the general node 31.

[0008] This 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, it refers to the cache in which the correspondence between the virtual network address and the physical network address is entered, and converts it into the post-relay packet 35 addressed to the physical network address. Send out. This post-relay packet 3
The format of No. 5 is shown in FIG. In the figure,
β is the information to which the physical network address after moving and the portion of the protocol header are 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. Thus, the post-relay packet 35 is transferred to the mobile node 33.
And is restored to the original pre-relay packet 34 before movement. Upon relaying, when the gateway located on the route receives the post-relay packet 35, it 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. Further, when the response packet is returned from the mobile node 33 to the general node 31, the physical network address and the virtual network address of the mobile node 33 are propagated to the general node 31.

As described above, in the VIP method, 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 continuously communicate before and after the movement. However, the general node 31 and the gateway 32 need to be able to interpret the virtual network address.

[0011]

However, according to the above-mentioned node position transparent method of the prior art, all the nodes on the network trying to communicate with the mobile node are virtual VIs.
Since it is necessary to expand the function so that the P address can be interpreted, there is a problem that all existing nodes must be modified.

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

In view of the above problems, the present invention manages the addresses of mobile computers which can be continuously communicated before and after the movement by a mobile computer to which an address is assigned for each network as the network moves. An object of the present invention is to provide a mobility management device, a packet relay device that relays packets, and a communication system including these.

[0014]

In order to achieve the above object, the mobility management device of the present invention is provided on a mobile node having a home address that does not change even when it is moved, and is connected between the mobile node and the network. A mobile management device that manages addresses of packets to be transmitted and received by the mobile node, the address holding means holding a home address of the mobile node and a current temporary address assigned at the destination of movement between networks; Packet receiving means for receiving a packet in which the destination address of the packet input from the packet and the temporary address held in the address holding means match, and the packet received by the packet receiving means is set as the destination address. Rewrite the temporary address to the home address and add the source address to the packet Address recovery means that rewrites to the address of the communication partner based on the information sent to the mobile node, and for the packet to be transmitted from the mobile node, the home address set as the source address is used as the temporary address and the destination address is set. The address conversion means for rewriting the address of the communication partner set as to 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.

The mobility management device may further include temporary address management means for acquiring a temporary address from a server device that manages an address on the network and writing it in the address holding means when moving. The packet relay device of the present invention is a packet relay device that relays 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. Address group holding means for holding the home address of the 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, and input from the network. By a relay packet receiving means for receiving from the network a packet in which the destination address of the packet that matches the home address held in the address group holding means, and a packet addressed to the address of this packet relay device, and the relay packet receiving means. Sends the received packet addressed to the 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 to the additional information. For the packet addressed to the own address received by the relay address conversion means and the relay packet reception means, the temporary address of the mobile node set as the source address is set as the home address and the destination address is set. And a relay address restoring means for rewriting the address of the packet relay device itself, which is included in the additional information, to the address of the general host.

The packet relay device may further include address correspondence acquisition means for receiving a packet including a correspondence relationship between a home address and a temporary address and writing the packet in the address group holding means. Further, the communication system of the present invention has 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 relays a packet including a correspondence between the temporary address and the home address when the temporary address is acquired, after the mobile node moves. A control packet including information indicating whether to start or end and the home address of the mobile node is transmitted, and in the packet relay device, the address group holding means corresponds to the set of the home address and the temporary address, and Holds a flag indicating whether or not to relay the packet having the packet, the address correspondence obtaining means sets the flag of the address group holding means based on the control packet transmitted from the mobile node, and the relay packet receiving means , If the flag indicates that the packet is not relayed, the packet is not received. It may be.

[0018]

With the above means, the packet receiving means in the mobility management device of the present invention receives the packet in which the destination address of the packet input from the network and the temporary address held in the address holding means match. In the received packet, the address restoring means rewrites the temporary address set as the destination address into the home address, and the source address into the address of the communication partner based on the information added to the packet, and the mobile node 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 by the address translation means, and the address of the communication partner set as the destination address is connected to the network to which the home address belongs. It is rewritten to the address of the packet relay device and the address of the communication partner is added as additional information.

Further, the temporary address management means of the mobility management device acquires the temporary address from the server device which manages the address on the network and writes it in the address holding means when moving. In the packet relay device of the present invention, the relay packet receiving means is a packet whose destination address of the packet input from the network and the home address held in the address group holding means match, and a packet addressed to the address of the packet relay device. Receives packets from the network. The packet addressed to the home address received by the relay packet receiving means is rewritten by the relay address converting means to the address of the communication partner of the mobile node set as the source address to the address of the packet relay device itself, and as the destination address. The home address of the set 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 means is a packet in which the temporary address of the mobile node set as the source address is set as the home address and the destination address is set by the relay address restoring means. 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 relation between the home address and the temporary address and writes it in the address group holding means. In the communication system of the present invention, a mobile node having a mobility management device transmits / receives a packet to / from another node via a packet relay device.

Further, 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 acquisition means of the packet relay device. The address correspondence obtaining means sets the flag of the address group holding means based on the control packet. The relay packet receiving means controls its operation according to the value of the flag.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A mobile communication device of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment of the present invention.
FIG. 3 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,
It is provided with an address group holding unit 4 and an address correspondence acquisition unit 5, and is connected to a network via a line control unit 7.

The relay packet receiving unit 1 receives the packet to be relayed by referring to the address group holding unit 4 among the packets input from the network through the line control unit 7. The relay packet receiving unit 1 fetches a packet to be relayed by, for example, NIT provided by SunOS.
This can be done through the interface. The address translation unit 2 translates the address of the packet addressed to the mobile node from the general node among the packets received by the relay packet reception unit 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 before the movement of the mobile node to the temporary address after the movement, The original source address is set as additional information. The home address of the mobile node is the address before the move in the first move after the start of communication, and the temporary address of the mobile node is the address in the newly assigned move destination.

The address restoring unit 3 converts the address of the packet addressed to the general node from the 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 group holding unit 4 manages the packet relay management table 6 which holds the address group of the home address (relay source address) and the temporary address (relay destination address) of the mobile node. Packet relay management table 6
Is the relay packet reception unit 1 and the address correspondence acquisition unit 5
Is accessed via the address group holding unit 4, and is used by the relay packet receiving unit 1 for determining a relay target packet and managing the address of the mobile node. An example of the packet relay management table is shown in FIG. In the figure, "relay source address" indicates the home address of the mobile node. The "relay destination address" indicates a temporary address of the mobile node. The "flag" indicates whether or not to relay the packet addressed to the relay source address of the entry. When this flag is on, relay is performed when a packet addressed to the relay source address is captured, and when the flag is off, relay is not performed even if the packet of the relay source is captured. The on / off state of this flag is set by the address correspondence acquisition unit 5.

The address correspondence acquisition unit 5 receives from the mobile node a control packet indicating the correspondence between the home address and the temporary address, and a packet for controlling the flag, and writes it to the packet relay management table 6 according to the instruction of the packet. , Update. The format of the control packet transmitted from the mobile node 14 is shown in FIG. Figure 6
(A) is a format when a mobile node moves and requests a packet to be relayed immediately. A "source address", a "destination address", and a "flag" indicating whether or not to start the relay Composed of. FIG. 6 (b),
(C) is a format for instructing the start and end of relaying, and is composed of a "relay source address", a "relay destination address" whose value is 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 showing a configuration of a second mobile communication device (hereinafter, referred to as a mobility management device). In the figure, the mobility management device 20 on the mobile node is provided on the mobile node, and includes a relay packet receiving unit 21, an address restoring unit 22, and an address converting unit 2.
3 and a temporary address management unit 25, which are connected to the network via the line control unit 26 and to the upper communication control unit 27.

The relay packet receiving unit 21 determines whether 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. I will check. As a result, if it matches the temporary address, the packet is passed to the address restoring unit 22, and if it 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 reception 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 translation unit 23 translates 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 whose source address is the home address and whose 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 translation unit 23, the address translation unit 23
Rewrites the transmission destination address from the address of the general node to the address of the packet relay device, rewrites the transmission source address from the home address to the current temporary address β, and transmits via the line control unit 26.

The temporary address management unit 25 receives allocation of a temporary address in the destination network. This allocation can be done manually by the network administrator, or in 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) It may be performed by an address management server such as a server. FIG. 6 (d) shows the format of a packet for transmitting a temporary address from the address management server to the mobile node when the address management server allocates it. Upon 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 higher-level communication control unit 27 inputs / outputs a packet to be transmitted / received notified to the mobility management device 20 by an application, and controls communication such as connection / disconnection of 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, and a general node 13.
And a mobile node 14.

In the figure, the packet relay device 10 is
It is the device shown in FIG. 1, and an address S is assigned. The gateway 12 connects networks and passes packets from one network to another network. The general node 13 is the mobile node 1
It is assumed that the other party of the communication of No. 4 is assigned the address r.

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 respectively indicate the flow of packets. The packet A is a packet sent from the general node 13 and addressed to the home address α of the mobile node 14. An example of the format of this packet A is shown in FIG. This format is "Ethernet header", "I
P packet ”and“ dest. ”And“ s ”in the IP packet
"rc." is the source address and destination address.

The packet B is a packet whose address has been translated by the packet relay device 10 and which has been sent to the current temporary address β of the mobile node 14. The format of this packet B is shown in FIG. "Additional information" is added to this format. Packet C is a packet sent to the address of the packet relay device 10 when the packet is sent from the mobile node 14 to the general node 13. The format of this packet C is shown in FIG.

The packet D is a packet whose address is translated from the packet C by the packet relay device 10 and which is sent to the address r of the general node 13. The format of this packet D is shown in FIG. Operations 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 when Mobile Node 14 Moves) In FIG. 3, the mobile node 14 is initially connected to the position indicated by the broken line and has the home address α, and then moves to the position indicated by the solid line and temporarily moves. It is assumed that the address β is assigned. The temporary address β is given by the control packet shown in FIG. 6D from the address management server (not shown) on the network via the line controller 26 according to an instruction from the higher-level communication controller 27. This control packet is acquired and held by the temporary address management unit 25. This temporary address may be acquired before or after moving.

The mobile node 14 that has acquired the temporary address β
After the transfer, the
The control packet shown in (a) is transmitted with the flag on to request relay. The control packet is received by the address correspondence acquisition unit 5 of the packet relay device 10 and is written in the packet relay management table 6 in the address group 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 device 10 is ready to relay packets.

When the mobile node 14 notifies the control packet shown in FIG. 6 (a) of only the address correspondence with the flag off, the control packet shown in FIG. 6 (b) is then transmitted and relayed. May be requested to start. Or later,
The operations 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 or not the mobile node 14 has moved.
This is because the general node 13 is premised on an existing device. (Packet A → packet relay device → packet B: address translation) The packet A (see FIG. 4A) sent 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 whether or not there is 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 relay destination address β corresponding thereto is extracted. Further, the relay packet reception 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 translation unit 2 rewrites the transmission destination address of the packet A from the relay source address α to the relay destination address β, and sets the transmission source address to the address r of the general node 13.
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 is translated in this way is packet B (see FIG. 4B).
The packet B whose address has been converted is sent to the network via the line controller 7. (Packet B → mobile node 14: reception) The relay packet reception unit 21 in the mobility management device on the mobile node 14 is
The packet B is received via the line controller 26. The relay packet receiving unit 21 determines that the destination address of the packet B is
It is checked whether or not the address matches the temporary address β held in the temporary address management unit 25 or the home address α of itself. As a result of the check, if the packet matches the temporary address, the packet is passed to the address restoring unit 22, and if it matches the home address, the packet is passed to the upper communication control unit 27. In the case of the present embodiment, since the received packet B coincides with the temporary address, the received packet B is restored by the address restoration unit 22
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
As a response packet to the packet, the mobile node 14 sends out a packet C (see FIG. 4C) in which the destination address and the source address of the received packet B are set in reverse.

More specifically, a packet whose source address is the home address α and whose destination address is the original destination address r is passed from the upper communication control unit 27 to the address conversion unit 23. Address conversion unit 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 via the line control unit 26. The packet thus transmitted is packet C.

In this way, 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 restoration) Since the destination address of the packet C is the address S of the packet relay device 10, the packet relay device 1
It is received by the relay packet receiving unit 1 of 0.

In the packet relay device 10, the relay packet receiving unit 1 extracts the source address of the packet C and stores it in the "relay destination address" of the packet relay management table 6.
Search for an address that matches. In the case of the present embodiment, since the matching address β exists, the relay source address α corresponding thereto is taken out. The relay packet receiving unit 1 transfers the packet C and the relay source address α obtained from the packet relay management table 6 to the address restoring unit 3. As a result, the address restoring unit 3 changes the 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 packet D rewritten in this way is sent 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, the packet D is received by the general node 13.

When the transmission source of the mobile node is the current temporary address, no address conversion may be performed. In this case, since the packet transmission destination address sent from the mobile node to the network remains the original transmission destination address, the packet can communicate with the original communication partner without going through the packet relay device. In this case, when the relay packet receiving unit 21 of the mobile node receives a packet having a destination as a temporary address and no additional information, the relay packet receiving unit 21 may pass the packet directly to the upper communication control unit 27.

[0045]

As described above, according to the above-mentioned prior art node position transparent method of the present invention, all nodes on the network that attempt to communicate with the mobile node are virtual VIPs.
Since it is necessary to expand the function so that the address can be interpreted, there is a problem that all existing nodes must be modified.

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

In view of the above problems, the present invention can be applied to a device on an existing network for a mobile node that moves between networks while changing an address, and the mobile node continuously communicates before and after moving. It is an object of the present invention to provide a packet relay device that enables the above easily. As described above, according to the mobile communication device of the present invention, the mobility management device on the mobile node sets the additional information 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 expanding the functions of the general node and the gateway.

Specifically, in the general node, since the address change due to the movement of the mobile node can be hidden, the application program on the general node which operates while communicating with the mobile node is unique to the manufacturer. However, there is an effect that communication with the mobile node can be continued. Also, in the mobile node,
The address restoration 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 moving.

In addition, since all the 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 drawings]

FIG. 1 is a diagram showing 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 a packet relay device according to the embodiment.

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

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

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

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

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

[Explanation of symbols]

 1 relay packet receiving unit 2 address converting unit 3 address restoring 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 mobile management device 21 relay Packet receiving unit 22 Address restoring unit 23 Address converting unit 25 Temporary address managing unit 26 Line control unit 27 Communication control unit

Claims (6)

[Claims] 1. A mobility management device which is provided on a mobile node having a home address that does not change even when the mobile node moves, is connected between the mobile node and a network, and manages an address of a packet to be transmitted and received by the mobile node. , An address holding means for holding the home address of the mobile node and a current temporary address assigned at the destination of movement between networks, a destination address of a packet input from the network, and a temporary address held in the address holding means Packet receiving means for receiving a packet having a match with and a packet received by the packet receiving means,
The temporary address set as the destination address should be rewritten to the home address, the source address should be rewritten to the address of the communication partner based on the information added to the packet, and the address restoration means to be passed to the mobile node and the mobile node should transmit For packets, the home address set as the source address is used as 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 of the above as additional information. 2. The mobility management device further comprises temporary address management means for acquiring a temporary address from a server device managing an address on the network and writing the address in an address holding means when moving. 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, to which the packet relay device is connected. Address group holding means for holding the home address of the mobile node having a home address in the network and the temporary address assigned at the destination of the movement associated with the movement between networks, and the destination of the packet input from the network A packet whose address matches the home address held in the address group holding means, a relay packet receiving means for receiving a packet addressed to the address of this packet relay device from the network, and a home address received by the relay packet receiving means Set as the source address for packets addressed to The address of the communication partner of the specified mobile node 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 as additional information. For the packet addressed to the own address received by the relay address conversion means and the relay packet reception means, the temporary address of the mobile node set as the source address is used as the home address,
A packet relay device comprising: a relay address restoring means for rewriting the address of the packet relay device itself set as a destination address to the address of a general host included in the additional information. 4. The packet relay device further comprises address correspondence acquisition means for receiving a packet including a correspondence relationship between a home address and a temporary address and writing the packet in an address group holding means. The packet relay device described. 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. In the mobility management device, the temporary address management means, when the temporary address is acquired, starts relaying a packet including a correspondence between the temporary address and a home address after the mobile node moves. A control packet including information indicating whether to terminate or the home address of the mobile node is transmitted, and in the packet relay device, the address group holding means has the address in association with the set of the home address and the temporary address. A flag indicating whether to relay the packet is held, the address correspondence obtaining means sets the flag of the address group holding means based on the control packet transmitted from the mobile node, and the relay packet receiving means sets the flag. The packet is not received when the flag indicates that the packet is not relayed. 5 communication system described.