JPH06337824A - Transfer packet receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] A network address that receives a packet transferred to a destination network of a mobile host to which a home address is assigned without receiving an extra route, and has a limited number of network addresses at the destination. Don't waste your money. The data unit 28 holds the correspondence between the home address Hx of the mobile host 33 and the directed broadcast address By of the network Y, and the transfer packet generation unit 31 sets the directed broadcast address By in the received packet 37. A transfer packet to which the transfer packet identifier p is added is generated and transmitted. The transfer packet identification unit 23 determines whether or not the identifier p exists in the received packet, and when it exists, the address comparison unit 24 determines whether the home address of the transfer packet matches the home address Hx of the home address holding unit 20. Judge whether
When they match, the packet restoring unit 25 restores the original packet 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention According to the present invention, a mobile host, which is a mobile communication device such as a computer device that performs network communication while moving, is transferred from another network while being connected to the destination network. The present invention relates to a transfer packet receiving device for receiving a transfer packet.

[0002]

2. Description of the Related Art The following two types of methods are conventionally known as a method for a mobile host to receive a packet transferred to a destination network of a mobile host in the destination network.

The first conventional method is a method in which an address is assigned in a destination network and a packet transferred using the address is received (for example, a "mobile host location management device" Japanese Patent Application). Flat 04-2995
No. 31). Hereinafter, an operation example of the first method will be described with reference to FIGS. 4 and 5.

The mobile host 1 is assigned a home address Hx belonging to the home network X and a temporary address Ty in the destination network Y. Connected to the network X are a host 2 that transmits a packet 4 addressed to the home address Hx of the mobile host 1 and a packet transfer server 3 that transfers a packet 5 addressed to the home address Hx to a temporary address Ty of the migration destination. There is. The network X and the destination network Y are connected via a router R.

Host 2 in home network X
Transmits packet 4 addressed to home address Hx.
The format of the packet 4 is, as shown in FIG. 5A, composed of data and a header. The header is composed of a destination network address 6 (home address Hx) and a source network address 7 (address r of the host 2). It is made up. When the packet 4 is transmitted from the host 2, the packet transfer server 3 in the same network X
Receives packet 4, packet transfer server 3 converts packet 4 into packet 5 addressed to temporary address Ty,
Transfer to the destination network Y via the router R.
The format of the transfer packet 5 is, as shown in FIG. 5B, that the packet 4 received from the host 2 is used as a data part, and the data part is used as a header for the destination network address 6 (temporary address Ty) and the source. Network address 7 (address s of packet transfer server 3)
Is added. The mobile host 1 receives the transfer packet 5 based on the temporary address Ty in the destination network Y, confirms that the home address Hx is included, and then restores the packet 4 and passes it to the upper layer.

In the second conventional method, a server for temporarily receiving the transferred packet is provided in the destination network, and the server sends an address corresponding to the data link layer to the mobile host (for example, Ethernet address in Ethernet). ) Is used for transmission. As a reference for this method, for example, [J. Ioannidis, D. Ducham
p, and GQMaguire Jr. "IP-based Protocols for Mob
ile Internetworking "ACM SIGCOMM, Sep. 1991]. The operation example of this second method will be described below with reference to FIGS. 6 and 7.

In the Ethernet LAN shown in FIG. 6, a home address H is assigned to the mobile host 8, but this home address H is an address that does not belong to any network. Connected to the network X are a host 9 that sends a packet 12 addressed to the home address H of the mobile host 8 and a server 10 that receives the packet 12 and performs format conversion and transfer.
The network X and the destination network Y of the mobile host 8 are connected via a router R. A server 11 that receives a transfer packet 13 sent from the server 10 via the router R and transfers it to the mobile host 8 is connected to the destination network Y.

The host 9 transmits the packet 12 addressed to the home address H to the server 10 existing on the same network X. The format of the packet 12 is (a) in FIG.
As shown in FIG. 5, it is composed of data and a header, and the header is composed of a destination network address 6 (home address H) and a source network address 7 (address r of the host 9). Packet 1 from host 9
The server 10 that has received 2 holds the address s2 of the server 11 existing on the network Y to which the mobile host 8 having the home address H moves, and the server 11
The transfer packet 13 encapsulated in the destination is transmitted via the router R. The format of the transfer packet 13 is
As shown in (b) of FIG. 7, the packet 12 received from the host 9 is used as a data part, and this data is used as a header for the destination network address 6 (the address s2 of the server 11) and the source network address 7 (of the server 10). The address s1) is added.

The server 11 which has received the transfer packet 13
Takes out the packet 12 encapsulated in the transfer packet 13 and, as a packet at the data link layer level, extracts the destination Ethernet address 15 (the Ethernet address pm for the mobile host 8) and the source Ethernet address 16 (the server). The transfer packet 14 having the Ethernet address ps of 11 as a header is transmitted to the mobile host 8. The format of the transfer packet 14 is shown in FIG. Since the source Ethernet address 16 (pm) is given to the mobile host 8 in advance, the mobile host 8 can receive the transfer packet 14 from the server 11, and the home address H
After confirming that the packet 12 is included, the packet 12 is restored and passed to the upper layer.

[0010]

However, in the first conventional method, it is necessary for the mobile host 1 to be assigned with the temporary address Ty of the destination network Y.
There was a problem of wasting a limited number of network addresses.

Further, in the second conventional method, the server 11 is interposed between the router R and the mobile host 8 in the destination network Y, and the extra route causes a loss of time and communication cost. There is a problem that the server 11 is required in addition to the increase in the number of servers.

The present invention was devised in view of the above circumstances, and provides a transfer packet receiving device which does not waste a limited number of network addresses and does not pass an unnecessary route in a destination network. The purpose is to provide.

[0013]

A transfer packet receiving apparatus according to the present invention is a transfer server apparatus which is connected to a home network of a mobile host (a network to which a home address belongs) and which transfers a packet to a destination network of the mobile host. A packet transmission / reception device mounted on the mobile host, wherein the transfer server device has a home address of the mobile host (an address that does not change even when the mobile host moves through the network) and a directed broadcast address in the destination network. And a packet receiving unit that receives a packet addressed to the home address, a directed broadcast address as a destination address from the correspondence relationship in the data unit for the received packet, and a transfer packet. It is And a transfer packet generator for generating a transfer packet to which the home address is added, and a transfer packet transmitter for transmitting the transfer packet. The packet transmitting / receiving device holds its own home address. A home address holding unit that
A packet receiving unit, a transfer packet identifying unit that determines whether or not an identifier indicating that the packet is the transfer packet is present in the received packet, and a transfer packet received when the packet is determined to be the transfer packet. An address comparison unit that determines whether or not the home address matches the home address of the home address holding unit, and a packet restoration unit that restores the original packet before transfer when both home addresses match. It is what

[0014]

In the transfer server device, the correspondence between the home address of the mobile host and the directed broadcast address of the destination network is held in the data part of the transfer server device, and the transfer packet is transferred to the packet whose destination address is the home address. The generation unit sends a transfer packet to which the directed broadcast address and the identifier indicating the transfer packet are added. In the packet transmission / reception device of the mobile host, the transfer packet identification unit determines whether the received packet includes an identifier,
The address comparison unit determines whether the home address held in the home address holding unit matches the home address in the received transfer packet, and when they match, the packet restoration unit restores the original packet. . In this case, since the packet transferred to the destination network is transferred using the directed broadcast address as the destination address, it is not necessary to assign a network address to the mobile host from the destination network. Also, since the destination address of the transferred packet is the directed broadcast address, the transfer of the packet from the transfer server device to the mobile host is carried out directly, and an extra route such as a server in the destination network is created. You do not need a special relay device to take.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A transfer packet receiving apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1A is a block diagram showing the electrical construction of a packet transmitting / receiving device mounted on a mobile host, and FIG. 1B is an electrical diagram of a transfer server device connected to the home network of the mobile host. It is a block diagram which shows a dynamic structure. FIG. 2 is a block diagram showing a schematic configuration of a local network configured by Ethernet.

First, the configuration of FIG. 2 will be described.
33 is a mobile host which is the object of packet transfer and is given and holds the home address Hx, X is the home network of the mobile host 33, and Y is the mobile host 3.
3 is a destination network, 34 is a host that sends a packet 37 to the home address Hx of the mobile host 33,
35 is a transfer server device that exists on the home network X and transfers the packet 37 to the destination network Y.
6 is a router that connects the home network X and the destination network Y, and 37 is a host 34 that is a mobile host 33.
Is a packet to be transmitted to the home address Hx of the transfer server device 35, 38 is a transfer packet to which the transfer server device 35 is transferred to the destination network Y using a broadcast address restricted to the network Y, that is, a directed broadcast address, and 38 '. A packet of the transfer packet 38 at the data link layer level in the network Y, that is, a packet including an Ethernet header, 39 is a non-target mobile host having a home address Ha different from the home address Hx of the mobile host 33, and 40 is an existing host Is.

An address r is assigned to the host 34, and an address s is assigned to the transfer server device 35. The router 36 holds pr as the Ethernet address on the network Y side. Mobile host 33,
39 and the existing host 40 are connected to the network Y. Both the mobile hosts 33 and 39 are equipped with the packet transmitting / receiving apparatus A of FIG. 1A according to the present invention, which will be described later. Home address Hx belonging to home network X
The mobile host 33 that holds is the mobile host to which the packet is to be transferred. The mobile host 39 holding the home address Ha that does not belong to the home network X is not a transfer target. The existing host 40 does not include the packet transmission / reception device A.

FIG. 1A shows a specific structure of the packet transmitting / receiving apparatus A mounted on the mobile hosts 33 and 39. In FIG. 1A, 17 is a lower communication control unit corresponding to the data link layer and below, and 18 is a higher communication control unit corresponding to the network layer and above. The broadcast address acquisition unit 19 is means for acquiring a broadcast address restricted to the destination network Y, that is, a directed broadcast address By. The home address holding unit 20 stores the home address Hx assigned to the mobile host 33 so that it does not change even when moving, and the home directed broadcast address which is a broadcast address restricted to the home network X to which the home address Hx belongs. Bx
Is a means of holding and. The movement notification unit 21 creates and transmits a movement notification packet including the home address Hx and the destination directed broadcast address By to the transfer server device 35 via the lower communication control unit 17. Is.

The packet receiving unit 22 is means for receiving the packet corresponding to the network layer passed through the lower communication control unit 17. The transfer packet identification unit 23 determines whether or not the packet passed from the packet reception unit 22 includes an identifier p for identifying the packet as a transfer packet. If the identifier p exists, the transfer packet identification unit 23 determines that packet. It is means for sending to the address comparing section 24 described later, and sending the packet as it is to the higher-level communication control section 18 when the identifier p does not exist. The address comparison unit 24
The home address Hj in the transfer packet passed from the transfer packet identifying unit 23 is compared with the home address Hx held in the home address holding unit 20 to determine whether or not it matches. It is a means for sending the packet to the packet restoring unit 25, and discarding the transferred packet when they do not match. The packet restoration unit 25 receives the transfer packet from the address comparison unit 24, restores the original packet 37 before the transfer whose home address Hx is the destination network address 6, and restores the restored original packet 37 to the upper communication control unit. It is a means for sending to 18.

FIG. 1B shows a specific configuration of the transfer server device 35 connected to the home network X.
In FIG. 1B, 26 is a line control unit for controlling a physical communication line, and 27 is a line notification unit that receives the movement notification packet transmitted from the movement notification unit 21 in the mobile host 33. The movement notification receiving unit 28 is a correspondence relation (H) between the home address Hx of the mobile host 33 and the destination directed broadcast address By.
x; By) is a data part for holding.

The data updating section 29 is a moving notification receiving section 27.
By checking the correspondence (Hx; By) included in the movement notification packet received by, and determining whether or not the home address Hx of them exists in the data part 28,
A means for updating the data section 28 to the directed broadcast address By corresponding to the home address Hx when it exists, and for writing the corresponding relationship (Hx; By) to the data section 28 when it does not exist. Is. The packet receiving unit 30 is means for receiving the packet 37 addressed to the home address Hx of the mobile host 33 stored in the data unit 28 via the line control unit 26. The transfer packet generation unit 31 uses the correspondence relationship (Hx; By) stored in the data unit 28 for the packet 37 received by the packet reception unit 30 to move to the destination directory corresponding to the home address Hx of the mobile host 33. Tid broadcast address By is added as a destination address, its own address s is added as a source address, and an identifier p indicating a transfer packet is added.
Is added to the header to generate the transfer packet 38. The transfer packet sending unit 32 is means for passing the transfer packet 38 generated by the transfer packet generating unit 31 to the line control unit 26 in order to send the transfer packet 38.

Next, the operation of the transfer packet receiving apparatus configured as described above will be described.

It is now assumed that the mobile host 33 has moved to the network Y and is connected to the network Y. Then, first, the broadcast address acquisition unit 19 of the mobile host 33 acquires the directed broadcast address By of the destination network Y and passes it to the movement notification unit 21. The movement notification unit 21 refers to the home address Hx stored in the home address holding unit 20 and the home directed broadcast address Bx belonging to the home network X, and refers to the home address Hx and the destination directed broadcast address By. The transfer notification packet including the correspondence relationship (Hx; By) with the destination address set to the directed broadcast address Bx is sent to the transfer server device 35 via the lower communication control unit 17.

In the transfer server device 35, the movement notification receiving unit 27 receives the movement notification packet sent via the line control unit 26, and the movement notification receiving unit 27 is included in the movement notification packet. Home address Hx and destination directed broadcast address By
The correspondence relationship (Hx; By) with The data update unit 29 receives the correspondence (H
x; By) to search the data part 28 according to
When the home address Hx corresponding to 8 exists, the corresponding directed broadcast address By
On the other hand, when the home address Hx does not exist in the data section 28, the received correspondence (Hx; B
y) is written in the data section 28. Now you are ready.

In the home network X, the host 34 sends a packet 37 addressed to the home address Hx onto the network X. An example of the format of the packet 37 is shown in FIG. 6 is a destination network address (home address Hx), and 7 is a source network address (address r of the host 34). The packet receiving unit 30 in the transfer server device 35 includes the data unit 28.
With reference to the home address Hx registered in, the packet 37 including the home address Hx is received and passed to the transfer packet generation unit 31. The transfer packet generation unit 31 sets the directed broadcast address By registered in the data unit 28 as a destination address, and adds a header having an identifier p indicating a transfer packet to the head of the packet 37. Then, the transfer packet 38 is generated, and the transfer packet 38 is passed to the transfer packet sending unit 32. Transfer packet sending unit 32
Sends the received transfer packet 38 to the destination network Y via the line control unit 26.

The format of the transfer packet 38 is shown in FIG. 6 is the destination network address (the destination directed broadcast address By),
7 is a source network address (transfer server device 35
Addresses s) and 41 are fields for storing the identifier p. As for the identifier p, TCP / IP (Transmission Contr
(ol Protocol / Internet Protocol), the identification can be dealt with by specially providing a protocol number indicating a transfer packet by using a field indicating a protocol number in an IP packet header.

The transfer packet 38 sent from the transfer server device 35 is sent to the destination network Y via the router 36. The router 36 determines that the destination address included in the transfer packet 38 is the directed broadcast address By of the destination network Y, and transmits the broadcast address pB of the Ethernet address which is an address corresponding to the data link layer. The transfer packet 38 'set to the destination Ethernet address is sent to the network Y. The format of the transfer packet 38 'including the Ethernet header is shown in FIG. 42 is a destination Ethernet address, and 43 is a source Ethernet address.

Next, the operation when the mobile host 33 connected to the destination network Y receives the transfer packet 38 'will be described. The packet receiving unit 22 that has received the transfer packet 38 ′ via the lower communication control unit 17
The transfer packet 38 ′ is passed to the transfer packet identifying unit 23. The transfer packet identification unit 23 determines whether or not the received packet includes an identifier p indicating that the packet is a transfer packet. When the identifier p is included, the transfer packet 38 ′ is sent to the address comparison unit 24. When there is no identifier p, the packet is directly passed to the upper communication control unit 18. The address comparison unit 24 having received the transfer packet 38 'compares the home address Hj included in the transfer packet 38' with the home address Hx held in the home address holding unit 20, and the two match. In that case, the transfer packet 38 'is passed to the packet restoring unit 25, and if there is no match, the transfer packet 38' is discarded. The packet restoring unit 25 restores the same original packet 37 (see (a) of FIG. 3) as before the transfer, which is the destination address of the home address Hx included in the received transfer packet 38 ', and restores it. It is passed to the upper communication control unit 18.

Incidentally, another mobile host 39 is also equipped with the packet transmitting / receiving apparatus A of the present invention shown in FIG. However, the home address it holds is Ha. In the mobile host 39, when the transfer packet 38 'is received, since the identifier p is included in the transfer packet 38', the transfer packet 38 'is passed from the transfer packet identifying section 23 to the address comparing section 24. Since the home address Hx included in 38 'does not match the home address Ha held in the home address holding unit 20, the transfer packet 38' is discarded in the address comparison unit 24.

The existing host 40 does not include the packet transmitting / receiving apparatus A shown in FIG.
Since the identifier p indicating the transfer packet cannot be recognized, the received transfer packet 38 'is discarded as it is.

As described above, the packet 37 sent from the host 34 to the home address Hx is restored as the original packet 37 only in the corresponding mobile host 33.

A device having the same function as the transfer server device 35 is provided on the host 34 so that the packet 37 addressed to the home address Hx is converted into the transfer packet 38 and transmitted from the stage before being transmitted to the network. You may comprise.

[0034]

As described above, according to the present invention, the packet to be transferred to the destination network is transferred as the packet having the directed broadcast address as the destination address. It is not necessary to assign the address of the network to the host, and it is possible to prevent the waste of a limited number of network addresses. Furthermore, since the packet transfer from the transfer server device to the mobile host is performed directly, a relay device such as a server that takes an extra route in the destination network is unnecessary, and it is possible to prevent time loss and communication cost increase.

[Brief description of drawings]

FIG. 1 shows an electrical configuration of a packet transmission / reception device installed in a mobile host and an electrical configuration of a transfer server device connected to a home network of a mobile host in a transfer packet receiving device according to an embodiment of the present invention. It is a block diagram shown.

FIG. 2 is a block diagram showing a schematic configuration of a local network configured by Ethernet in the embodiment.

FIG. 3 is a packet format for a transfer packet receiving device in the embodiment.

FIG. 4 is a block diagram showing a schematic configuration of a local network for a transfer packet receiving device according to a conventional first method.

FIG. 5 is a packet format in the first conventional method.

FIG. 6 is a block diagram showing a schematic configuration of a local network for a transfer packet receiving device according to a second conventional method.

FIG. 7 is a packet format in the second conventional method.

[Explanation of symbols]

1 ... Mobile Host 2 ... Host 3 ... Packet Transfer Server 4 ... Packet 5 ... Transfer Packet 6 ... Destination Network Address 7 ... Source Network Address 8 ... Mobile Host 9 ... Host 10 ...
Server 11 ... Server 12 ... Packet 13 ... Transfer packet 14 ... Packet 15 ... Destination Ethernet address 16 ... Source Ethernet address R ... Router 17 ... Lower communication control unit 18 ... Upper communication control unit 19 ... Broadcast address acquisition unit 20 ... home address holding unit 21 ... movement notification unit 22 ... packet reception unit 23 ... transfer packet identification unit 24 ... address comparison unit 25 ... packet restoration unit 26 ... line control unit 27 ... movement notification reception unit
28 ... Data part 29 ... Data updating part 30 ... Packet receiving part 31 ... Transfer packet generating part 32 ... Transfer packet sending part 33 ... Mobile host 34 ... Host 35 ... Transfer server device A ... Packet transmitting / receiving device 36 ... Router 37 ... Packet 38 ... Transfer packet 38 '... Transfer packet 39 ... Mobile host
40 ... Existing host X ... Home network Y ...
Destination network Hx ... Home address p
... Identifier indicating transfer packet By ... Directed broadcast address pr ... Ethernet address pB ... Broadcast address of Ethernet address

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // H04B 3/54 4229-5K

Claims (1)

[Claims] 1. A transfer server device, which is connected to a home network of a mobile host (a network to which a home address belongs) and transfers a packet to a destination network of the mobile host, and a packet transmission / reception device mounted on the mobile host. The transfer server device includes a data part that holds a correspondence relationship between a home address of a mobile host (an address that does not change even when the mobile host moves through a network) and a directed broadcast address in a target network, and the home address. A packet receiving unit that receives a packet addressed to the packet, and a transfer in which the directed broadcast address is set as a destination address from the correspondence relationship in the data unit and the identifier indicating the packet is transferred and the home address are added to the received packet. Pa A transfer packet generation unit that generates a transfer packet and a transfer packet transmission unit that transmits the transfer packet. The packet transmission / reception device includes a home address storage unit that stores its own home address, and a packet reception unit. A transfer packet identification unit that determines whether or not the received packet includes an identifier that indicates the transfer packet, and a home address in the transfer packet that is received when the transfer packet is determined to be the transfer packet. It is composed of an address comparison unit that determines whether the home address of the home address holding unit matches, and a packet restoration unit that restores the original packet before transfer when both home addresses match. A transfer packet receiving device characterized by: