KR100745049B1 - Method for managing the mobility of mobile node - Google Patents

Abstract

A method for managing the mobility of a mobile node is provided to communicate with a correspondent node without a problem of the triangle routing by mapping a CoA(Care of Address) of IPv6 and an IPv4 address of the mobile node in the router. A method for managing the mobility of a mobile node includes the steps of: snatching a register request message transmitted from a mobile node to a corresponding node to receive the register request message when moving the mobile node from a home agent of an IPv4 network to an external agent(S1); mapping a CoA(Care of Address) of IPv4 assigned to the mobile node by the external agent with the CoA of IPv6 assigned to the mobile node by the router by responding to the register request message(S3); and transmitting the register request message to the mobile node by responding to the register request message(S5).

Description

{Method for managing the mobility of mobile node}

1 illustrates a mobile network in which an IPv4 network and an IPv6 network coexist.

FIG. 2 is a diagram for describing triangular routing occurring when a mobile node moves from a home agent to an external agent of an IPv4 network.

3 illustrates a network for explaining a method for managing mobility of a mobile node according to an embodiment of the present invention.

4 is a functional block diagram illustrating an example of a movement manager according to the present invention.

5 shows an example of a mapping table according to the present invention.

6 is a flowchart illustrating a mobility management method of a mobile node according to an embodiment of the present invention.

7 is a flowchart illustrating the generation of the mapping table according to the present invention in more detail.

8 is a flowchart illustrating a method of determining whether a mobile node continues to exist in an external agent in accordance with the present invention.

The present invention relates to network communication, and more specifically, to a mobile node of an IPv4 network and a corresponding node (CN) of an IPv6 network, the mobility of the mobile node in a NAT-PT-based router interworking different Internet protocols. It is about how to manage.

The number of Internet users is increasing due to the performance improvement of mobile nodes such as portable computers and PDAs and the development of wireless communication technology. If the number of wireless Internet users is increasing as it is, the existing Internet Protocol Version 4 (IPv4) addressing system cannot meet the increasing IP address requirements. Therefore, studies are being actively conducted to provide mobility using IPv6 (Internet Protocol Version 6), which is currently attracting attention as the next generation Internet protocol.

Mobile IPv6 provides mobility while using the features of IPv4, so it can support mobility more effectively than mobile IPv4 and has excellent scale and scalability. As computers become smaller and Internet access is available through smaller terminals, mobility support for this becomes inevitable. As a result, efforts to support mobility in the current Internet environment using the Internet Protocol (IP) are underway in the IP routing for Wireless / Mobile Hosts Charter (IETF) of the Internet Engineering Task Force (IETF). Since the standard for supporting mobility of IPv4 was enacted, work on supporting mobility of IPv6 has been made.

Currently, in order to be replaced with mobile IPv6 from mobile IPv4, mobile IPv4 and mobile IPv6 coexist with each other for a long time from the introduction of IPv6. 1 illustrates a mobile network in which a mobile IPv4 network and a mobile IPv6 network coexist.

Referring to FIG. 1, a mobile node MN is connected to a mobile IPv4 network, and a corresponding node CN communicating with the mobile node is connected to a mobile IPv6 network, respectively. On the other hand, a mobile IPv4 network and a mobile IPv6 network are connected to a NAT-PT based router BR.

The router BR allocates the IPv6 CoA to the mobile node connected to the home agent HA of the mobile IPv4 network, and assigns the CoA of IPv4 to the corresponding node CN connected to the IPv6 network. When a mobile node (MN) connected to a home agent (HA) of an IPv4 network transmits a packet to a corresponding node (CN) connected to an IPv6 network, the destination address of the packet is an IPv4 assigned to the corresponding node (CN). Is CoA. The CoA of IPv4 assigned to the correspondent node CN is mapped to the actual IPv6 address of the correspondent node CN, and the router BR maps the CoA of IPv4 assigned to the correspondent node CN to the correspondent node CN. Convert to the actual IPv6 address.

On the other hand, when a packet is transmitted from the correspondent node CN connected to the IPv6 network to the mobile node MN connected to the IPv4 network, the destination address of the packet is a CoA of IPv6 assigned to the mobile node MN. have. The CoA of IPv6 assigned to the mobile node (MN) is mapped to the actual IPv4 address of the mobile node (MN), and the router (BR) maps the CoA of IPv6 assigned to the mobile node (MN). Convert to the actual IPv6 address.

FIG. 2 is a diagram for describing triangular routing that occurs when a mobile node MN moves from a home agent HA to an external agent FA in an IPv4 network.

When the mobile node MN moves out of the home agent HA of the IPv4 network to the foreign agent FA, the mobile node MN is assigned an IPv4 care of address from the foreign agent FA. The mobile node (MN) sends a registration request message to the home agent (HA) in order to register an IPv4 address allocated from an external agent (FA), and the home agent (HA) responds with a registration response message to the mobile node (HA). MN).

On the other hand, a registration request message is sent to inform the corresponding node CN of the IPv6 network communicating with the mobile node MN of the movement of the mobile node MN. However, since the corresponding node CN connected to the IPv6 network uses a different Internet protocol from the mobile node MN, the corresponding node CN cannot receive a registration request message sent from the mobile node MN. Therefore, when the correspondent node CN connected to the IPv6 network transmits the packet to the mobile node MN, the packet is sent back to the mobile node MN of the foreign agent FA via the home agent HA.

When the mobile node (MN) moves from the home agent (HA) of the IPv4 network to the foreign agent (FA), the corresponding node (CN) of the IPv6 network communicating with the mobile node (MN) requests registration from the mobile node (MN). The message cannot be received and the corresponding node CN does not know that the mobile node MN has moved to the foreign agent FA. Therefore, a problem of triangular routing occurs in which a packet transmitted to the mobile node MN is transmitted to the home agent HA of the mobile node MN and then retransmitted from the home agent HA to the foreign agent FA.

It is an object of the present invention to provide mobility of IPv4 mobile nodes (MNs) that communicate with IPv6's corresponding nodes (CNs) in NAT-PT-based routers located between IPv4 and IPv6 networks and interworking different Internet protocols. It is to provide a way to manage.

In order to achieve the object of the present invention, the mobility of the mobile node (MN) of IPv4 communicating with the corresponding node of IPv6 in a NAT-PT-based router located between an IPv4 network and an IPv6 network and interworking different Internet protocols. The managing method includes a registration request message transmitted from the mobile node MN to the corresponding node CN when the mobile node MN moves from the home agent HA of the IPv4 network to the foreign agent FA. Receiving instead of CN) (step a), in response to a registration request message, mapping an IPv4 address assigned to a mobile node (MN) by an external agent (FA) with a CoA of IPv6 assigned to the mobile node (MN) by a router (B) and sending a registration response message to the mobile node (MN) in response to the registration request message (step c).

Hereinafter, a mobility management method of a mobile node (MN) according to the present invention will be described in more detail with reference to the accompanying drawings.

3 illustrates a network for explaining a method for managing mobility of a mobile node (MN) according to an embodiment of the present invention.

Between an IPv4 network and an IPv6 network, a NAT-PT based router relays communication between a mobile node (MN) of IPv4 and a corresponding node (CN) of IPv6. That is, the NAT-PT based router allocates CoA of IPv6 to a mobile node MN of IPv4 and allocates CoA of IPv4 to a corresponding node CN of IPv6. In the packet transmitted from the mobile node MN to the correspondent node CN, the destination address is a CoA of IPv4 assigned to the correspondent node CN, and the router is mapped with the CoA of IPv4 assigned to the correspondent node CN. The destination address of the packet is converted and transmitted to actual IPv6 of the correspondent node CN. On the other hand, in the packet transmitted from the correspondent node CN to the mobile node MN, the destination address is a CoA of IPv6 assigned to the mobile node MN, and the router has a CoA of IPv6 assigned to the mobile node MN. Transmit the destination address of the packet to the actual IPv4 address of the mapped mobile node (MN) and send it.

When the mobile node MN moves from the home agent HA to the foreign agent FA, the mobile node MN sends a registration request message to the home agent HA to inform mobility. The transmitted registration request message includes an IPv4 address assigned by the foreign agent FA to the mobile node MN. The home agent HA registers the IPv4 address assigned to the mobile node MN as the new address of the mobile node MN in response to the registration request message and transmits a registration response message to the mobile node MN. Arrows (a) and (b) represent registration request messages sent from the mobile node MN to the home agent HA and registration response messages sent from the home agent HA to the mobile node MN, respectively.

On the other hand, the registration request message for notifying the movement of the mobile node MN to the corresponding node CN of the IPv6 network in communication is transmitted. The mobility manager of the NAT-PT-based router extracts the IPv4 address assigned to the mobile node (MN) by the foreign agent from the registration request message and maps the table to manage the mobility of the mobile node (MN) based on the extracted IPv4 address. Create After the mapping table is created, the mobile manager sends a registration response message to the mobile node MN.

4 is a functional block diagram illustrating an example of a movement manager according to the present invention.

Referring to FIG. 4, the extractor 11 intercepts a registration request message sent from the mobile node MN to the corresponding node CN in the middle, and the IPv4 assigned to the mobile node MN by the external agent FA. Extract the address. The mapping table generation unit 13 first maps the extracted IPv4 address and the CoA of the IPv6 assigned to the mobile node (MN) by the router, and moves the IPv4 address and the router of the mobile node (MN) from the home agent (HA). A mapping table is generated by secondly mapping CoAs of IPv6 allocated to the node MN. In the generated mapping table, the extracted IPv4 address and the CoA of IPv6 assigned to the mobile node (MN) are recorded in the first column and assigned to the mobile node (MN) and the IPv4 address of the mobile node (MN) in the home agent (HA). CoA of one IPv6 is recorded in the second column. When the mapping table is generated, the message transceiving unit 15 transmits a registration response message to the mobile node MN through a router.

When a packet is transmitted from the correspondent node CN to the mobile node MN, the destination address of the transmitted packet is a CoA of IPv6 assigned to the mobile node MN by the router, and the mapping unit 19 is generated. Search the first column of the mapping table and change the destination address of the packet to the IPv4 address of the mobile node mapped with the CoA of IPv6. The destination address of the changed packet is the address of IPv4 assigned to the mobile node MN by the foreign agent FA, and the packet is transmitted directly from the corresponding node CN to the mobile node MN. Therefore, the mobile node MN and the corresponding node CN can continue to communicate without the problem of triangular routing.

Meanwhile, the generated mapping table includes a movement field to indicate that the mobile node MN has moved to the foreign agent FA. The moving field is indicated by a predetermined bit, and the moving field is maintained for a predetermined time. The updater 17 inquires the retention time of the mobile field and, when the retention time has elapsed, sends a message for confirming whether the mobile node MN is validly present in the foreign agent FA through the message transceiver 15. Transmit to mobile node MN. If no message is received from the mobile node MN of the foreign agent FA in response to the confirmation message, the updater 17 deletes the first column from the generated mapping table and updates the second column to the first column. do. The update unit 17 also deletes the moving field from the mapping table.

On the other hand, when the mobile node MN returns from the external agent FA to the home agent HA, the updater 17 deletes the first column of the mapping table and updates the second column to the first column. The update unit 17 also deletes the moving field from the mapping table.

5 shows an example of a mapping table according to the present invention.

5 and 3, when the mobile node MN is connected to the home agent HA, the IPv4 address of the mobile node MN is 163.180.118.2, and the mobile node MN is an external agent FA. ), The IPv4 address allocated from the external agent is 163.180.119.2. Meanwhile, the CoA of IPv6 assigned to the mobile node (MN) by the NAT-PT based router is 2001: 230 :: 1. In the first column of the mapping table, when the mobile node (MN) moves to the foreign agent (FA), the address of IPv4 allocated from the foreign agent (FA) and the CoA of IPv6 allocated to the mobile node (MN) from the router are mapped to each other. In the second column, when the mobile node MN is connected to the home agent HA, an IPv4 address and a CoA of IPv6 assigned to the mobile node MN from the router are mapped to each other.

6 is a flowchart illustrating a mobility management method of a mobile node (MN) according to an embodiment of the present invention.

Referring to FIG. 6, when a mobile node MN moves from a home agent HA to an external agent FA, a registration request message is received from the mobile node MN (step 1). When the mobile node MN moves to the foreign agent FA, the mobile node MN sends a registration request message to the corresponding node CN to notify its movement. A mobile manager of a router which interworks communication between a mobile node (MN) and a corresponding node (CN) by interworking different Internet protocols between an IPv4 network and an IPv6 network, intercepts a registration request message sent to the corresponding node (CN) in the middle. Receive a chat registration request message.

In response to the registration request message, the mobile manager generates a mapping table that maps the IPv4 address assigned to the mobile node (MN) by the external agent (FA) and the CoA of IPv6 assigned to the mobile node (MN) by the router. (Step 3). The step of generating a mapping table according to the present invention is described in more detail with reference to FIG.

Referring to FIG. 7, the foreign agent FA intercepts a registration request message transmitted from the mobile node MN to the corresponding node CN and is included in the registration request message. Extracts the IPv4 address (step 21). The IPv4 address of the extracted IPv4 and the CoA of IPv6 allocated by the router to the mobile node (MN) are first mapped (step 23), and the IPv4 address of the mobile node (MN) and the router are mobile nodes (MN) by the home agent (HA). The CoA of IPv6 allocated to the second mapping is mapped (step 25). Based on the first and second mapping results, a mapping table is generated between the mobile node (MN) IPv4 address and the CoA of IPv6 assigned to the mobile node (MN) by the router. The generated mapping table includes the IPv4 address of the mobile node (MN) and the mobile node (MN) in the home agent (HA) in the first column that maps the extracted IPv4 address and the CoA of IPv6 assigned to the mobile node (MN) by the router. A second column in which CoAs of IPv6 allocated to MN) are mapped is included. Preferably, the generated mapping table includes a movement field indicating that the mobile node MN has moved to the foreign agent FA, and the movement field is maintained for a predetermined time.

 Referring to FIG. 6 again, when a packet is transmitted from the corresponding node CN to the mobile node MN (step 7), the first column of the mapping table is retrieved (step 9). The destination address of the packet transmitted from the correspondent node CN to the mobile node MN is the CoA of IPv6 assigned to the mobile node MN by the router, and is mapped to the CoA of IPv6 in the first column of the mapping table ( The packet is directly transmitted to the IPv4 P address of the MN (step 11).

On the basis of the registration request message sent from the mobile node MN to the corresponding node CN, it is determined whether the mobile node MN has returned to the home agent HA again (step 13), and the mobile node MN determines the home agent. When returning to HA, the moving field and the first column of the mapping table are deleted and the second column is updated to the first column (step 15).

8 is a flowchart illustrating a method of determining whether a mobile node continues to exist in an external agent in accordance with the present invention.

When the retention time of the mobile field included in the mapping table has elapsed, a message is sent to the mobile node to confirm whether the mobile node continues to exist in the foreign agent (step 31). In response to the confirmation message, it is determined whether a response message has been received from the mobile node (step 33), and when the response message indicating that the mobile agent continues to exist is received, the maintenance time of the mobile field is initialized (step 35). On the other hand, if the response message is not received from the mobile node MN, the first column of the mobile field and the mapping table is deleted and the second column is updated to the first column (step 37).

 Meanwhile, the above-described embodiments of the present invention can be written as a program that can be executed in a computer, and can be implemented in a general-purpose digital computer that operates the program using a computer-readable recording medium.

The computer-readable recording medium may be a magnetic storage medium (for example, a ROM, a floppy disk, a hard disk, etc.), an optical reading medium (for example, a CD-ROM, DVD, etc.) and a carrier wave (for example, the Internet). Storage medium).

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

In the mobility management method of a mobile node (MN) according to the present invention, when a mobile node (MN) moves from a home agent (HA) of an IPv4 network to an external agent (FA), a CoA and an external node of IPv6 allocated to the mobile node by a router By mapping the IPv4 addresses of the mobile node MN in the agent FA, the mobile node MN may continue to communicate with the corresponding node CN even if the mobile node MN moves to an external agent without the problem of triangular routing.

Claims (6)

A method for managing mobility of a mobile node (MN) of an IPv4 network communicating with a corresponding node (CN) of the IPv6 network in a NAT-PT based router located between an IPv4 network and an IPv6 network and interworking different IP protocols, (a) When the mobile node (MN) moves from the home agent (HA) of the IPv4 network to the foreign agent (FA), it intercepts the registration request message sent from the mobile node (MN) to the corresponding node (CN) Receiving; (b) mapping a CoA of IPv4 assigned to the mobile node (MN) by the foreign agent (FA) with a CoA of IPv6 assigned to the mobile node (MN) by the router in response to the registration request message; And  (c) sending a registration response message to the mobile node (MN) in response to the registration request message. The method of claim 1, wherein step (b) Extracting an IPv4 address assigned to a mobile node (MN) by an external agent (FA) from the registration request message; Firstly mapping the extracted IPv4 address and CoA of IPv6 assigned to the mobile node (MN) by the router;  Second mapping, at the home agent (HA), an IPv4 address of a mobile node (MN) and a CoA of IPv6 allocated to the mobile node (MN) by the router; And Generating a mapping table between a CoA of IPv6 allocated to a mobile node (MN) and an IPv4 address of the mobile node (MN) by the router based on the first and second mapping results. Way. The method of claim 2, wherein the mapping table And a mobile field for indicating that the mobile node (MN) has moved from a home agent (HA) to an external agent (FA). The method of claim 3, wherein Retrieving the mapping table when transmitting a packet from the corresponding node CN of the IPv6 network to the mobile node MN; And And transmitting the packet to the IPv4 address of the mobile node (MN) mapped with the CoA of IPv6 in the first column of the mapping table based on the search result. 4. The method of claim 3, wherein when the mobile node (MN) returns back to the home network of an IPv4 network, Deleting the movement field; And Deleting the first column from the mapping table and updating the second column to the first column. The method of claim 3, wherein the holding time of the movement field has elapsed. Sending a message to the mobile node (MN) to confirm that the mobile node (MN) is validly present in an external agent (FA); In response to the confirmation message, if the mobile node MN does not exist in the foreign agent FA, deleting the first column of the mapping table and updating the second column to the first column; And And if the mobile node (MN) is present in an external agent (FA) in response to the confirmation message, initializing a maintenance time of the mobile field.

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