JP2001168906A - Position information managing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize optimum routing, without the need for adding a function to an existing terminal. SOLUTION: In a communication system consisting of a mobile IP network A comprising routers having an IP packet transfer function, IP networks B, C interconnected with the mobile IP network A to transfer IP packets, and terminals 27 connected fixedly to the IP networks B, C and having an IP packet communication function, a border gateway BG installed at each border between the mobile IP network A and the IP networks B, C by each IP network totally stores and manages information the same as position information managed by all home agents in the mobile IP network A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a location information management system, and more particularly, to a mobile terminal under a mobile IP network and a terminal fixedly connected to an IP network having no terminal mobility management function. The present invention relates to a position information management system that optimizes a communication path between two terminals when performing communication using an IP packet.

[0002]

2. Description of the Related Art Conventionally, as a terminal mobility management technique in an IP network, a mobile IP defined by the Internet Engineering Task Force (IETF) has been used.
(RFC2002, RFC2003, RFC2004)
It has been known. FIG. 9 is a system configuration diagram when mobile IP is applied, and FIG. 10 shows a procedure in which a mobile terminal registers position information based on the system configuration shown in FIG.

[0003] (1) The mobile terminal 15
Move from the subnet A (16) including the home agent (hereinafter, referred to as "HA" including in the figure) 1 (11) managing the location information to another subnet B17 (arrow R1). (2) Foreign agent in subnet B (17) (hereinafter referred to as “FA” including in the figure) 2 (14)
Corresponds to the position information of the mobile terminal 15, and is represented by FA2 (14)
The care-of address, which is also the IP address of the mobile terminal 15,
(Arrow R2). (3) The FA2 (14) notifies the HA1 (11) of the care-of address assigned to the mobile terminal 15 (arrow R3).

FIG. 11 shows an operation of transmitting an IP packet from the terminal 27 of the IP network A (19) to the mobile terminal 15 based on the system configuration shown in FIG. (1) First, the IP packet has a unique I
HA1 derived from P address (home address)
It is transmitted to (11) (arrow S1). (2) In HA1 (11), location information corresponding to the mobile terminal 15, that is, a care-of address is searched, and HA1 is searched.
From (11), the IP packet is transferred to the care-of address, that is, FA2 (14) (arrow S2).

[0005] FIG. 12 is a diagram for explaining a route optimization method for an IP packet communication operation, which is being studied in the IETF. (1) Upon receiving the IP packet from the FA2 (14), the mobile terminal 15 notifies the terminal 27 of the current care-of address (arrow S3). (2) The terminal 27 holds the correspondence between the home address of the mobile terminal and the notified care-of address, and performs subsequent packet communication with the care-of address of the mobile terminal 15 (arrow S4).

[0006]

As described in the IETF draft, the route optimization method according to the above technology has a function of recognizing a notice of care-of address from a mobile terminal,
It can be realized only by a terminal that can exercise a necessary protocol operation such as a function of associating a home address and a care-of address, and there is a problem that it does not operate on an existing terminal.

[0007] An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a newly required function at a boundary between a mobile IP network and an IP network, so that an existing terminal can be provided. Without making any changes, when a mobile terminal under the mobile IP network and a terminal fixedly connected to an IP network having no terminal mobility management function perform communication by IP packets, both terminals It is an object of the present invention to provide a position information management system that optimizes a communication path between the two.

[0008]

In order to achieve the above object, according to the present invention, devices (border gateways) BG1 and BG2 having functions equivalent to those required to be added to a fixed terminal in the prior art are provided. Mobile IP network A and IP
It is arranged at the boundary between the networks B and C. As a result, in the IP packet communication between the terminal and the mobile terminal, it is possible to optimize the route without adding a function to the terminal and hardly changing the function of the network device.

More specifically, in the location information management system according to the present invention, location information (care-of address) of each terminal is managed for all mobile terminals subscribed to a certain subnet, and A home agent having a function of searching for the position information (care-of address) of the terminal from the unique address (home address) of each terminal when a packet transmission request is made, and transmitting a packet with the searched care-of address as a destination; Not subscribed to the subnet, temporarily assigns a care-of address dynamically to mobile terminals located in the subnet, and sets the correspondence between the home address of the terminal and the care-of address to the terminal. Function to notify the home agent that manages the IP address, and when there is a packet transmission request to the terminal, A foreign agent having a function of transmitting an IP packet with a home address as a destination address, a plurality of subnets including a router having an IP packet transfer function, and a router having an IP packet transfer function. Mobile IP
An IP network, comprising a network and a router having an IP packet transfer function, interconnected with the mobile IP network and capable of transferring IP packets; and an IP network fixedly connected to the IP network and using IP packets. In a communication system including a terminal having a communication function, a mobile unit I is provided for each IP network.
A device (border gateway) installed at the boundary between the P network and the IP network collectively holds and manages the same information as the location information managed by all the home agents in the mobile IP network. I do.

[0010] In the location information management system according to the present invention, the border gateway uses an IP address (home address) unique to a mobile terminal in the mobile IP network based on a destination address of a packet received from another IP network. )When,
The mobile terminal searches for position information that holds the correspondence with the IP address (care-of address) assigned in the destination network, and if the care-of address corresponding to the home address is registered, the searched care-of address is replaced with the IP packet of the IP packet. It has an IP packet sending function of sending an IP packet to the head of the mobile terminal and using the care-of address as a destination address as a destination address.

Further, in the location information management system according to the present invention, in the subnet group composed of the plurality of subnets, no contract is made with any of the subnets constituting the subnet group, and the subnet group is temporarily assigned to the subnet group. For the mobile terminal present, a second care-of address is dynamically assigned separately from the care-of address assigned in each subnet included in the subnet group, and the home address and the care-of address of the mobile terminal are assigned. A function of notifying the home agent managing the terminal of the correspondence between the home address and the second care-of address, when the mobile terminal is moving from outside the subnet group, When there is a packet transmission request to the terminal, the second care-of address is removed from the received IP packet, and the home address is removed. Characterized by comprising a mobile IP network configuration deployed a representative foreign agent having a function of sending the IP packet to the care-of address corresponding to the scan as the destination address.

[0012]

Embodiments of the present invention will be described below in detail with reference to preferred embodiments shown in the drawings.

[Embodiment 1] FIG. 1 shows a system configuration which is a premise of an embodiment corresponding to claims 1 and 2. In the configuration shown in FIG. 1, in addition to the conventional configuration, the IP network A (1
8) Location information management for holding and managing the same information as the location information managed by all the HAs in the IP network A (18) in the router at the boundary between the IP network B (19) and the IP network C (20). Border gateways (BG) 1 (28) and BG2 (29) having a function and an IP packet transfer function are provided. Here, 21 and 22 are respectively
IP network A (18), IP network B (19), IP network C (2
0). Also, 23, 2
4, 25 and 26 denote border routers between IP networks.

Referring now to FIG. 2, a method of registering location information in a BG in this embodiment will be described in detail. (1) Subnet A (16) including HA1 (11) in which mobile terminal 15 manages location information of mobile terminal 15
(Home network) to other subnet B (17)
(Arrow R1). (2) The FA2 (14) in the subnet B (17) corresponds to the location information of the mobile terminal 15, and the IP of the FA2 (14)
A care-of address, which is also an address, is assigned to the mobile terminal 15 (arrow R2).

(3) The FA 2 (14) notifies the HA 1 (11) of the care-of address assigned to the mobile terminal 15 (arrow R3). (4) The HA 1 (11) further notifies the BG 1 (28) of the care-of address of the mobile terminal 15 (arrow R4). (5) After storing the correspondence between the home address of the mobile terminal 15 and the care-of address, the BG1 (28) notifies the BG in the IP network A (18) of the correspondence (arrow R5).

Next, with reference to the flowchart shown in FIG. 3, the processing in the BG at the time of location registration will be described.
First, at block 50, when the home address and the care-of address are notified from the HA, at block 51,
The location information for BG storage management is searched. Block 5
At 2, if the home address is not found, at block 56 both the home address and the care-of address are registered in the location information.

If the home address is found in block 52, the care-of address notified to the home address in block 53 and the care-of address already registered are calculated as follows. Perform a comparison to see if they are different. If the care-of address is different in block 53, the care-of address is updated in block 54. If it is the same care-of address in block 53, the process proceeds to block 55, and the position information is not updated.

Next, a method of transmitting an IP packet from the terminal 27 to the mobile terminal 15 in the embodiment will be described in detail with reference to FIG. (1) First, an IP packet is transmitted to BG1 (28) at the boundary between IP network B (19) and IP network A (18) (arrow S1). (2) In BG1 (28), location information corresponding to the mobile terminal 15, that is, a care-of address is searched, and
From the G1 (28), the care-of address, that is, FA2 (1
The IP packet is transferred to 4) (arrow S2).

The processing in the BG at the time of packet transfer will be described below with reference to the flowchart shown in FIG.
First, at block 60, after the packet arrives,
At block 61, the home address indicated in the packet is retrieved. Then, in block 62, the position information managed and maintained by the BG is searched. If the care-of address corresponding to the home address is not found in block 63, block 6 is sent to the home address.
At 5, the IP packet is transferred.

On the other hand, when the care-of address corresponding to the home address is searched in block 63, the searched care-of address is added to the destination address of the packet in block 64, and is sent to the care-of address. , Block 65 transfers the IP packet. According to the above embodiment, it is possible to optimize the communication path in the IP network A (18).

[Embodiment 2] FIG. 6 shows a system configuration diagram which is a premise of an embodiment corresponding to claim 3. In the configuration shown in FIG. 6, the subnet A (16) in the IP network A (18)
And the subnet group A (38) with the subnet B (17),
A subnet group B (39) is configured by the subnet C (36) and the subnet D (37), and the subnet group A (38) is not contracted with any of the subnets constituting the subnet group. The mobile terminal 15 existing in the subnet group is dynamically assigned a second care-of address separately from the care-of address assigned to each subnet included in the subnet group, and the home address of the terminal. And a function of notifying the HA managing the terminal of the correspondence between the home address and the second care-of address when the mobile terminal 15 is moving from outside the subnet group. And removing the second care-of address from the received IP packet at the time of a packet transmission request to the terminal, and changing the care-of address corresponding to the home address to Representative has the function of transmitting the IP packet as previously address FA1 to deploy (30). Similarly, in the subnet group B (39), the representative F
A2 (31) is deployed.

The location information registration procedure in this configuration will be described in detail with reference to FIGS. First, FIG. 7 will be described. (1) The mobile terminal 15 moves from the subnet A (16) to the subnet C (36) (arrow R1). (2) The FA 3 (33) in the subnet C (36) corresponds to the location information of the mobile terminal 15, and the IP of the FA 3 (33)
An IP address (care-of address) that is also an address is assigned to the mobile terminal 15 (arrow R2).

(3) The FA 3 (33) notifies the care-of address assigned to the mobile terminal 15 to the representative FA 2 (31) (arrow R3). (4) The representative FA2 (31) determines whether the mobile terminal 15 is already registered in the representative FA2 (31). (5) The representative FA 2 (31) recognizes that the mobile terminal 15 is not registered, and sends the mobile terminal 1 to the HA 1 (11).
The IP address of the representative FA2 (31) is notified as the care-of address of No. 5 (arrow R4).

(6) HA1 (11) further converts BG1 (2)
8) to notify the care-of address of the mobile terminal 15 (arrow R).
5). (7) After storing the correspondence between the home address and the care-of address of the mobile terminal 15, the BG1 (28) notifies the correspondence to all BGs in the IP network A (18) (arrow R6).

Next, FIG. 8 will be described. (1) The mobile terminal 15 moves from the subnet C (36) to the subnet D (37) (arrow R1). (2) The FA4 (35) in the subnet D (37) corresponds to the location information of the mobile terminal 15, and the IP of the FA4 (35)
An IP address (care-of address) that is also an address is assigned to the mobile terminal 15 (arrow R2).

(3) The FA 4 (35) notifies the care-of address assigned to the mobile terminal 15 to the representative FA 2 (31) (arrow R3). (4) The representative FA2 (31) determines whether the mobile terminal 15 has already been registered in the representative FA2 (31). (5) The representative FA2 (31) recognizes that the mobile terminal 15 is registered.

According to the above embodiment, it is possible to reduce the frequency of registration of the position information to the BG shown in the first embodiment while maintaining the optimum route. Note that the above embodiments are merely examples of the present invention, and the present invention is not limited to these embodiments.

[0028]

As described in detail above, when a terminal connected to an IP network having no terminal movement management function of a mobile terminal under the network performs communication by IP packet,
In the conventional method, as shown in FIG. 11, it is necessary to pass through the HA managing the mobile terminal, and the communication path is redundant. However, according to the present invention, as shown in FIG.
8) It is possible to obtain the effect of optimizing the communication path in the section. Further, according to the network configuration shown in claim 3, while maintaining the optimality of the route, claim 1 and claim 2
In this case, it is possible to reduce the frequency of registering the position information with the BG shown in FIG.

[Brief description of the drawings]

FIG. 1 is a diagram showing a system configuration according to the present invention.

FIG. 2 is a diagram showing a location information registration method according to the present invention.

FIG. 3 is a flowchart showing BG processing in position registration.

FIG. 4 is a diagram showing an IP packet communication operation in the present invention.

FIG. 5 is a flowchart showing BG processing in packet transfer.

FIG. 6 is a diagram illustrating a system configuration in which an IP network is hierarchized;

FIG. 7 is a diagram (part 1) illustrating a location information registration procedure in a system configuration in which the IP network is hierarchized.

FIG. 8 is a diagram (part 2) illustrating a location information registration procedure in a system configuration in which the IP network is hierarchized.

FIG. 9 is a diagram showing a system configuration of mobile IP.

FIG. 10 is a diagram showing a method of registering location information of mobile IP.

FIG. 11 shows a terminal 2 based on the system configuration shown in FIG.
FIG. 7 is a diagram showing an IP packet communication operation from the terminal 7 to the mobile terminal 15;

FIG. 12 is a diagram showing a route optimization method for an IP packet communication operation shown in FIG. 11;

[Explanation of symbols]

11, 13, 32, 34 Home agent (HA) 12, 14, 33, 35 Foreign agent (F
A) 15 mobile terminal 16, 17, 36, 37 subnet 38, 39 subnet group 18, 19, 20 IP network 21 communication line connecting IP network (A) and IP network (B) 22 IP network (A) and IP network (C) Communication line 23, 24, 25, 26 Border router 27 Terminal 28, 29 Border gateway (BG) 30, 31 Representative FA

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Ihara 2-3-1, Otemachi, Chiyoda-ku, Tokyo Inside Nippon Telegraph and Telephone Corporation (72) Inventor Yasushi Takagi 2-3-3, Otemachi, Chiyoda-ku, Tokyo No. 1 Nippon Telegraph and Telephone Corporation F-term (reference) CC05 CC07 JJ14 JJ25

Claims (3)

[Claims] 1. For each mobile terminal subscribed to a certain subnet, position information (care-of address) of each terminal is managed, and when a packet transmission request is issued to each terminal, a unique address (each address) of each terminal is managed. The home agent having a function of searching for the location information (care-of address) of the terminal from the home address) and transmitting a packet with the searched care-of address as a destination is not contracted with the subnet, and is temporarily contracted with the subnet. A function of dynamically assigning a care-of address to a mobile terminal located in the area, and notifying the home agent managing the terminal of the correspondence between the home address and the care-of address of the terminal; and When a packet transmission request is issued, the care-of address is removed from the received IP packet, and the home address is set as the destination address.
A foreign agent having a function of transmitting a packet, a plurality of subnets including a router having an IP packet transfer function, a mobile IP network including a router having an IP packet transfer function, and an IP packet transfer function. An IP network interconnected with the mobile IP network and capable of transferring IP packets, and a terminal fixedly connected to the IP network and having a communication function using IP packets. In a communication system, a mobile IP network is provided for each IP network by a device (border gateway) installed at a boundary between the mobile IP networks.
A location information management system, which collectively holds and manages the same information as the location information managed by all home agents in a network. 2. The method according to claim 1, wherein the border gateway is configured to determine an IP address (home address) unique to a mobile terminal in the mobile IP network based on a destination address of a packet received from another IP network. Is searched for position information that holds the correspondence with the IP address (care-of address) assigned in step 2. If the care-of address corresponding to the home address is registered, the searched care-of address is added to the beginning of the IP packet, and the care-of address is The location information management system according to claim 1, further comprising an IP packet sending function of sending an IP packet to a location where the mobile terminal is located, with the destination address as a destination address. 3. In a subnet group composed of the plurality of subnets, a contract is not made with any of the subnets constituting the subnet group, and a mobile terminal temporarily located in the subnet group is assigned to the subnet. A second care-of address is dynamically assigned separately from a care-of address assigned to each subnet included in the group, and a correspondence between the home address and the care-of address of the mobile terminal is held, Is a movement from outside the subnet group, a function of notifying the home agent managing the terminal of the correspondence between the home address and the second care-of address, and a request to send a packet to the terminal. Removing the second care-of address from the received IP packet, and setting the care-of address corresponding to the home address as a destination address. Positional information management system according to claim 1 or 2, further comprising a mobile IP network configuration deployed a representative foreign agent having a function of sending out the IP packet Te.