KR100749816B1 - Method for providing an ability of roaming from IPv6 network based on NEMO to IPv4 network - Google Patents

Abstract

The present invention relates to network communications, and more particularly, to a method for providing mobility to a mobile network moving from a mobile IPv6 network environment to an IPv4 network environment.

The method for providing mobility of a mobile network according to the present invention includes obtaining and storing IPv6 and IPv4 addresses of a tunnel agent (TA) existing between a mobile IPv6 network environment and a mobile IPv4 network environment, and storing them in a mobile router (MR); Acquiring an IPv4 care of address (MR) of a mobile router (MR) that has moved from the mobile IPv6 network environment to the mobile IPv4 network environment, and a flag indicating that the mobile router (MR) has moved to the IPv4 network environment is set. Transmitting a binding update message for forming a tunnel between the mobile router (MR) and the tunnel agent (TA) and a tunnel between the tunnel agent (TA) and the home agent (HA) and based on the binding update message. Forming a tunnel between the MR) and the tunnel agent (TA) and a tunnel between the tunnel agent (TA) and the home agent (HA). And that is characterized.

IPv4 Network, IPv6 Network, Mobile Network, NEMO, Tunneling

Description

A method for providing mobility of a mobile network moving from an NPE-based IPv6 network environment to an IPv4 network environment {Method for providing an ability of roaming from IPv6 network based on NEMO to IPv4 network}

FIG. 1 is a diagram illustrating a method of supporting mobility of a mobile router (MR) moving in an IPv6 network according to the NEMO basic protocol.

2 illustrates a network providing mobility of a mobile network, corresponding to one embodiment of the present invention.

3 is a flowchart illustrating a method of providing mobility of a mobile network according to an embodiment of the present invention.

4 is a flowchart illustrating a method of obtaining an IPv4 address and an IPv6 address of a tunnel agent (TA) in a mobile router (MR) in more detail.

5 is a flowchart illustrating a method of generating the binding update message and transmitting the generated binding update message to a home agent in more detail.

6 is a flowchart illustrating a method of transmitting the binding update message to the home agent HA through the tunnel agent TA in more detail.

FIG. 7 illustrates a method of communicating with a corresponding node CN through a tunnel between a home agent HA and a mobile router MR established through a tunnel agent TA.

FIG. 8 is a flowchart illustrating a method for newly establishing a tunnel between the mobile router MR and the tunnel agent TR when the mobile router MR moves to another link in an IPv4 network environment.

9 is a flowchart illustrating a method in which the mobile router MR, which has moved to the IPv4 network environment, returns to the IPv6 network environment.

The present invention relates to network communications, and more particularly, to a method for providing mobility to a mobile network moving from a mobile IPv6 network environment to an IPv4 network environment.

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 Internet Protocol Version 4 (IPv6), which is currently attracting attention as the next generation Internet protocol.

Mobile IPv6 provides mobility while retaining the features of IPv6, providing greater mobility and greater scalability than Mobile IPv4. With the miniaturization of computers and the availability of Internet access through small terminals, mobility support is 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.

Recently, in addition to the mobility of the terminal unit, mobility support technology of a mobile network for a case in which a moving means constituting a network such as a bus, an airplane, a car, and a train moves is also discussed. Discussion of mobility support technology in mobile networks is actively discussed by IETF's Network Mobility (NEMO) Working Group (WG). First, the NEMO Basic Protocol was established as a standard in RFC 3963 to extend mobile IPv6, a mobile terminal mobility technology, to provide seamless Internet access for mobile internal terminals. Standardization related to other expansions is underway.

FIG. 1 is a diagram illustrating a method of supporting mobility of a mobile router (MR) moving in an NEMO based IPv6 network environment.

When a mobile router (MR) connected to a home agent (HA) in an NEMO-based IPv6 network environment moves to an external agent (FA) in an NEMO-based IPv6 network environment, the mobile router (MR) receives a CoA from the external agent (FA). Acquire (Care of Address). The mobile router MR transmits a binding update message including the obtained CoA to the home agent HA through the relay router BR, and the home agent HA responds to the binding update message in response to the binding update message. Is transmitted to the mobile router (MR). Based on the binding update message and the binding acknowledgment message, the mobile router (MR) completes location registration with the home agent (HA), and provides mobility to the mobile network in an NEMO based IPv6 network environment.

The NEMO based IPv6 network environment described above provides mobility to the mobile network. However, because a protocol that supports mobility, such as NEMO-based IPv6 networks, is incompatible with other versions of networks, such as IPv4 networks, when a mobile network moves to an IPv4 network environment, There is no guarantee of continuous session connection.

Accordingly, an object of the present invention is to maintain a tunnel between a home agent (HA) and a mobile network by using a tunnel agent (TA) even when the mobile network moves from an IPv6 network environment to an IPv4 network environment. It is to provide a method for providing mobility to a mobile network.

In order to achieve the object of the present invention, a method for providing mobility of a mobile network including a mobile router (MR) between a NEMO-based mobile IPv6 network environment and a mobile IPv4 network environment, the mobile IPv6 network environment and the mobile Obtaining IPv6 and IPv4 addresses of Tunnel Agents (TAs) existing between IPv4 network environments and storing them in the mobile router (step a), moving from the mobile IPv6 network environment to a mobile IPv4 network environment Acquiring an IPv4 care of address (CoA) of the mobile router (MR) (step b), a flag indicating that the mobile router (MR) has moved to an IPv4 network environment is set, and the mobile router (MR) is set Binding update mesh to form tunnel between the tunnel agent (TA) and the tunnel agent (TA) and the home agent (HA) Sending a message (step c) and forming a tunnel between the mobile router (MR) and the tunnel agent (TA) and a tunnel between the tunnel agent (TA) and the home agent (HA) based on the binding update message. (d step).

Preferably, the step (a) may include (a1) acquiring an IPv4 address and an IPv6 address of the tunnel agent TA from the home agent HA (step a1), and setting a first flag for supporting mobility of the mobile network. Transmitting a set home agent search request message from the mobile router (MR) to a home agent (HA) (step a2), in response to the home agent search request message, an IPv4 address of the obtained tunnel agent TA and Transmitting a home agent (HA) search response message including an IPv6 address to a mobile router (MR) of the mobile network (step a3) and the tunnel agent (TA) in response to the home agent (HA) search response message; Storing the IPv4 address and the IPv6 address in the mobile router (MR) (step a4).

Preferably, the step (b) comprises receiving an Agent Advertisement message from a foreign agent (FA) of an IPv4 network to which the mobile network has moved (step b1) and based on the agent advertisement message. And (b2) obtaining an IPv4 CoA of the mobile router (MR).

Preferably, the step (c) includes setting a second flag for indicating that the mobile network has moved to the IPv4 network (step c1), and using the IPv4 address of the mobile router (MR) as a source address. Generating an IPv4 header having a TA IPv4 address as a destination address (step c2), an IPv6 header having an IPv6 address of a tunnel agent (TA) as a source address, and an IPv6 header of a home agent (HA) as a destination address; Generating (c3), generating a binding update message including the generated IPv4 header, the IPv6 header and the second flag (step c4), and generating the generated binding update message as a home agent of an IPv6 network (HA). It is characterized in that it comprises a step (c5 step) for transmitting through the tunnel agent (TA).

Hereinafter, a method of providing mobility of a mobile network according to the present invention will be described in detail with reference to the accompanying drawings.

2 illustrates a network providing mobility of a mobile network, corresponding to one embodiment of the present invention.

Referring to FIG. 2, a Mobile Node (MN) connected to a Mobile Router (MR) in an IPv6 network environment communicates with a Correspond Node. The plurality of mobile nodes MN connected to the mobile router MR form one mobile network.

If the mobile network continues to communicate with the corresponding note CN even when the mobile network moves to the IPv4 network environment, the mobile router MR sends a home agent search request message to the home agent HA and the home agent HA The home agent search response message is sent to the mobile router MR in response to the home agent search request message. The home agent search response message includes an IPv4 address and an IPv6 address of a tunnel agent TA existing between an IPv6 network environment and an IPv4 network environment.

When the mobile network moves to an IPv4 network environment, a tunnel between the mobile router MR and the tunnel agent TA is established by using the IPv4 address of the tunnel agent TA and the IPv6 address of the tunnel agent TA. By setting the tunnel between the tunnel agent (TA) and the home agent (HA) by using, it provides mobility of the mobile network even when the mobile network moves to the IPv4 network.

3 is a flowchart illustrating a method of providing mobility of a mobile network according to an embodiment of the present invention.

The mobile router MR to be provided with mobility of the mobile network acquires and stores the IPv4 address and the IPv6 address of the tunnel agent TA (step 40). Referring to FIG. 4, the above-described 40 steps of the mobile router MR obtaining the IPv4 address and the IPv6 address of the tunnel agent TA will be described in more detail.

The home agent HA connected to the IPv6 network environment obtains the IPv4 address and the IPv6 address of the tunnel agent TA existing between the IPv6 network environment and the IPv4 network environment (step 42). Preferably, in an NEMO-based IPv6 network environment, the home agent (HA) obtains a tunnel end point address and uses a dual stack transition mechanism (DSTM) to tunnel agents in the current network environment. Obtain an IPv4 address and an IPv6 address for the (TA). On the other hand, if the dual stack translation mechanism (DSTM) is not available, the IPv4 address and the IPv6 address of the tunnel agent (TA) are set to predetermined addresses, and the set IPv4 address and the IPv6 address are the IPv4 address and the tunnel agent (TA). Can be used as an IPv6 address.

 If the mobile network continues to provide mobility of the mobile network even when the mobile network moves, the mobile router (MR) connected to the IPv6 network environment generates a home agent discovery request message to generate an anycast address. (Step 44). In the home agent search request message, a first flag for providing mobility is set even when the mobile network moves to an IPv4 network environment.

The home agent HA, which knows the tunnel end point among the home agents HA near the mobile router MR, transmits a home agent search response message to the mobile router MR in response to the home agent search request message. (Step 46). The home agent search response message includes a field for setting the first flag and an information field for an IPv4 address and an IPv6 address of the tunnel agent.

The mobile router (MR) receiving the home agent search response message stores the IPv4 address and the IPv6 address of the tunnel agent (step 48).

Referring back to FIG. 3, the mobile router MR of the mobile network moving to the IPv4 network environment acquires a care of address (CoA) of IPv4 (step 50). The mobile router (MR) of the mobile network moving to the IPv4 network receives an agent advertisement message from a foreign agent (FA) existing in the IPv4 network. The mobile router (MR) obtains a new CoA in an IPv4 network environment from the agent advertisement message. The CoA means a new address allocated in the network environment in which the mobile router MR currently exists. By obtaining the IPv4 CoA in the IPv4 network environment, the mobile router MR detects that the mobile network has moved to the IPv4 network environment.

The mobile router MR acquiring the new CoA generates a binding update message and transmits the generated binding update message to the home agent HA through the tunnel agent TA (step 60). FIG. 5 is a flow chart illustrating in more detail the step 60 of generating the binding update message and transmitting the generated binding update message to a home agent HA.

Referring to Fig. 5, a second flag is set (step 61). The binding update message corresponding to an embodiment of the present invention includes a field for indicating that the mobile router (MR) has moved to the IPv4 network environment, and when it detects that the mobile router (MR) has moved to the mobile network, That is, when the IPv4 CoA is obtained, the second flag is set in the field.

Meanwhile, an IPv4 header is generated using the IPv4 CoA of the mobile router MR as the source address and the IPv4 address of the tunnel agent TA as the destination address (step 63). Further, an IPv6 header is generated with the IPv6 address of the tunnel agent TA as the source address and the IPv6 address of the home agent HA as the destination address (step 65).

The second flag is set, and generates a binding update message having an IPv4 header and an IPv6 header (step 67). The generated binding update message is transmitted to the home agent HA via the tunnel agent TA (step 69). Preferably, the IPv6 header is encapsulated for transmission to the home agent (HA) through the tunnel agent (TA). FIG. 6 is a flowchart illustrating step 69 of transmitting the binding update message to the home agent HA through the tunnel agent TA in more detail.

Referring to FIG. 6, the binding update message in which the second flag is set is transmitted to the tunnel agent TA (step 69-1). Upon receiving the binding update message, the tunnel agent TA decapsulates the encapsulated IPv6 header (step 69-3) and deletes the IPv4 header from the binding update message (step 69-5). The tunnel agent TA sends a binding update message from which the IPv4 header is deleted to the home agent HA (step 69-7).

Referring to FIG. 3 again, based on the binding update message, a tunnel between the mobile router MR and the tunnel agent TA and a tunnel between the tunnel agent TA and the home agent HA are established (step 70). . In response to the binding update message, the home agent HA transmits a binding acknowledgment message to the mobile router MR through the tunnel agent TA. The tunnel between the home agent (HA) and the tunnel agent (TA) is established based on the IPv6 header of the binding update message. Meanwhile, a tunnel between the tunnel agent TA and the mobile router is established based on the IPv4 header of the binding update message. In the NEMO-based IPv6 network, when communicating with the correspondent node (CN), the message must be transmitted only through a tunnel established between the home agent (HA) and the mobile router (MR), and in the present invention, the home is transmitted through the tunnel agent (TA). Maintain a tunnel between the agent HA and the mobile router MR.

FIG. 7 illustrates a method of communicating with a correspondent node CN through a tunnel between a home agent HA and a mobile router MR established through a tunnel agent TA.

Referring to FIG. 7, the correspondent node CN in the IPv6 network environment transmits a message having an IPv6 header, with the source address as the mobile node MN of the mobile network. The home agent HA receives the message sent from the corresponding node CN. Since the CoA of the mobile router (MR) to which the mobile node (MN) is connected is set to the IPv6 address of the tunnel agent (TA), the home agent (HA) is between the tunnel agent (TA) and the home agent (HA). The received message is transmitted to the tunnel agent TA through the tunnel set in. The tunnel agent TA converts an IPv6 address into a mapped IPv4 address and attaches an IPv4 header with the IPv4 CoA of the mobile router as a destination address to the message. The tunnel agent TA transmits the message including the IPv4 header to the mobile router MR through a tunnel established between the tunnel agent TA and the mobile router MR. The mobile router MR receiving the message deletes an IPv4 header from the message and sends the message to the mobile node MN.

The message transmission from the mobile node MN of the mobile network to the corresponding node CN proceeds in the reverse manner to the message transmission process from the corresponding node CN to the mobile node MN described above.

FIG. 8 is a flowchart illustrating a method for newly establishing a tunnel between the mobile router MR and the tunnel agent TR when the mobile router MR moves to another link in an IPv4 network environment.

Referring to FIG. 8, it is determined whether the mobile router MR has moved to another link in the IPv4 network environment (step 81). It is determined whether the mobile router (MR) has moved to another link in the IPv4 network environment based on obtaining a new IPv4 CoA from an external agent (FA).

When a mobile router (MR) obtains a new CoA from an external agent (FA), the mobile router (MR) uses an IPv4 header with the newly obtained CoA as the source address and the IPv4 address of the tunnel agent (TA) as the destination address. The second binding update message is transmitted to the tunnel agent TA (step 83). A second flag is set indicating that the second binding update message has moved to the IPv4 network environment.

The tunnel agent TA establishes a new tunnel between the tunnel agent TA and the mobile router MR in response to the second binding update message (step 85). Since the tunnel between the home agent (HA) and the tunnel agent (TA) does not change even when the mobile router (MR) moves to another link in the IPv4 network environment, only the tunnel between the tunnel agent (TA) and the mobile router (MR) is newly established. Do.

FIG. 9 is a flowchart illustrating a method in which the mobile router MR, which has moved to the IPv4 network environment, returns to the IPv6 network environment.

Referring to FIG. 9, it is determined whether the mobile router MR has returned to the IPv6 network environment (step 91). It is determined whether the mobile router MR returns to the IPv6 network environment based on obtaining a new IPv6 CoA from the home agent HA.

If the mobile router (MR) obtains a new IPv6 CoA from the home agent (HA), the mobile router (MR) is an IPv6 header with the newly acquired CoA as the source address and the IPv6 address of the home agent (HA) as the destination address. The third binding update message including the message is transmitted to the tunnel agent TA (step 93). The second flag is unset to indicate that the third binding update message has moved to the IPv6 network environment.

Upon receiving the third binding update message, the tunnel agent TA releases the tunnel between the tunnel agent TA and the mobile router MR and transmits a third binding update message to the home agent HA (step 95). . In response to the third binding update message, the home agent sets the CoA of the mobile router (MR) to the actual IPv6 address of the mobile router (step 97).

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 method of providing mobility of the mobile network according to the present invention, even when the mobile router (MR) moves to an IPv4 network environment, the tunnel of the mobile router (MR) and the home agent (HA) through the tunnel agent (TA) is maintained, Compared to the dual stack conversion mechanism or the Doors mechanism, this reduces the problem of tunnel overhead.

In addition, when a mobile router (MR) moves to another link in the moved IPv4 network, only the tunnel of the mobile router (MR) and the tunnel agent (TA) needs to be reset, so that an additional binding update message is transmitted to the home agent (HA). There is no.

Claims (14)

A method for providing mobility of a mobile network including a mobile router (MR) between an NEMO based mobile IPv6 network environment and a mobile IPv4 network environment, (a) acquiring an IPv4 address and an IPv6 address of the tunnel agent TA at the home agent HA; (b) transmitting from the mobile router (MR) to a home agent (HA) a home agent search request message having a first flag set to support mobility of a mobile network; (c) in response to the home agent search request message, transmit a home agent (HA) search response message including the obtained IPv4 address and the IPv6 address of the tunnel agent (TA) to the mobile router (MR) of the mobile network; Doing; (d) storing the IPv4 address and the IPv6 address of the tunnel agent (TA) in a mobile router (MR) in response to the home agent (HA) search response message; (e) obtaining an IPv4 care of address (CoA) of the mobile router (MR) that has moved from the mobile IPv6 network environment to a mobile IPv4 network environment; (f) A flag indicating that the mobile router (MR) has moved to an IPv4 network environment is set and a tunnel between the mobile router (MR) and the tunnel agent (TA) and a tunnel agent (TA) and a home agent (HA) is set. Transmitting a binding update message to form a tunnel between the; And (g) establishing a tunnel between the mobile router (MR) and the tunnel agent (TA) and a tunnel between the tunnel agent (TA) and the home agent (HA) based on the binding update message. To provide mobility for a mobile network. delete The method of claim 1, wherein in step (a) And a home agent (HA) obtains the IPv4 address and the IPv6 address of the tunnel agent (TA) using a dual stack IPv6 dominant transition mechanism. The method of claim 1, wherein in step (a) The IPv4 address and the IPv6 address of the tunnel agent (TA) are preset. The method of claim 1, wherein step (e) (e1) receiving an Agent Advertisement message from a foreign agent (FA) of an IPv4 network to which the mobile network has moved; And (e2) obtaining an IPv4 CoA of a mobile router (MR) based on the agent advertisement message. The method of claim 5, wherein the step (f) (f1) setting a second flag to indicate that the mobile network has moved to an IPv4 network; (f2) generating an IPv4 header having an IPv4 address of the mobile router MR as a source address and an IPv4 address of the tunnel agent TA as a destination address; (f3) generating an IPv6 header having an IPv6 address of the tunnel agent TA as a source address and an IPv6 address of the home agent HA as a destination address; (f4) generating a binding update message including the generated IPv4 header, the IPv6 header and the second flag; And (f5) transmitting the generated binding update message to a home agent (HA) of an IPv6 network through a tunnel agent (TA). The method of claim 6, wherein the generated IPv6 header is A method for providing mobile network mobility, characterized by being encapsulated in a binding update message. The method of claim 7, wherein the step (f5) Transmitting the generated binding update message to a tunnel agent (TA); Decapsulating the encapsulated IPv6 header; Deleting an IPv4 header of a binding update message at the tunnel agent (TA); And And using the decapsulated IPv6 header, transmitting a binding update message from which the IPv4 header has been deleted to a home agent (HA). The method of claim 8, wherein step (g) Establishing a tunnel between a mobile router (MR) and a tunnel agent (TA) using the generated IPv4 header; And Establishing a tunnel between a tunnel agent (TA) and a home agent by using the generated IPv6 header. The method of claim 9, A message transmitted to the mobile router MR by a tunnel established between the tunnel agent TA and the home agent HA is tunneled to the tunnel agent TA. The tunneled message is tunneled to the mobile router (MR) by a tunnel established between the tunnel agent (TA) and the mobile router (MR). 10. The method of claim 9, wherein the mobile router (MR) moves in an IPv4 network environment. and (h) establishing a new tunnel between the mobile router (MR) and the tunnel agent (TA). 12. The method of claim 11, wherein (h) Obtaining a new IPv4 CoA of the mobile router (MR); Transmitting a second binding update message to the tunnel agent TA using the new IPv4 CoA as a source address and an IPv4 address of the tunnel agent TA as a destination address; And And establishing a new tunnel between the mobile router (MR) and a tunnel agent based on the second binding update message. 10. The method of claim 9, wherein when the mobile router (MR) moves back to an IPv6 network, Generating and transmitting a third binding update message for which the second flag is not set to the home agent; And And setting the CoA of the mobile router (MR) to the actual IPv6 address of the mobile router (MR) instead of the IPv6 address of the tunnel agent (TA) based on the third binding update message. How to provide mobility. A computer-readable recording medium having recorded thereon a program for executing the method according to any one of claims 1 or 3 to 13 on a computer.

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