KR100765795B1 - Method and apparatus for providing handover information to mobile node - Google Patents

Abstract

A method and an apparatus for providing handover information to a mobile node are provided to previously check whether the mobile node is able to use an IPv6(Internet Protocol version6) prefix at a new POA(Point Of Attachment) before receiving an RA(Router Advertisement) message, thereby preventing unnecessary delay on the handover and efficiently using the bandwidth of the network by the handover. A method for providing handover information comprises the following steps of: allowing an information server to transmit information about the capability of a new POA(Point Of Attachment), which a mobile node will have access to, to the mobile node in(S200); and allowing the mobile node to determine whether an IPv6(Internet Protocol version6) prefix at the new POA by using the information about the capability of the new POA and generate an address used in data communication with the new POA according to a method determined according to whether the IPv6 prefix can be used(S210~S230).

Description

Method and apparatus for providing handover information to mobile node

1 is a diagram illustrating a mobile communication environment according to an embodiment of the present invention.

2 is a diagram illustrating a network layer of a mobile node according to an embodiment of the present invention.

3 is a diagram illustrating contents of a connection point capability information element according to an embodiment of the present invention.

4 is a diagram illustrating a configuration of a handover apparatus according to an embodiment of the present invention.

5 is a flowchart illustrating each step of the handover method according to an embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

1: mobile node

2, 3: Point of Attachment (PoA)

4: correspondence node (CN)

5, 6: Information Server (IS)

300: IP version 6 field

310: IP version 6 Prefix Available field

TECHNICAL FIELD The present invention relates to mobile communication and, in particular, to handover at a mobile node.

With the recent development of communication technology, the types of communication networks have also diversified. Representative examples include various links such as IEEE 802.11, IEEE 802.15, IEEE 802.16 based WLAN link, 3rd Generation Partnership Project (3GPP), 3GPP2 based cellular link, and the like. Accordingly, mobile nodes equipped with heterogeneous link interfaces for accessing various links have emerged, and Institute of Electrical and Electronics Engineers (IEEE) 802.21 has been established to support handover between various links.

The Institute of Electrical and Electronics Engineers (IEEE) 802.21 standard is intended to support Media Independent Handover (MIH) between various links. In the recently discussed IEEE 802.21 standard, along with other points, a PoA capabilities IE is used to convey information about the capabilities of a Point of Attachment (PoA) to a mobile node. It is also discussed.

The PoA capabilities IE includes the Internet Protocol (IP) version 4 and IP version 6 (IPv6), along with security, quality of service (QoS), and more. It also indicates whether it is supported.

However, even when the point of attachment (PoA) supports IP version 6 (IPv6), the prefix function of IPv6 may be used to generate an address for the mobile node to use in data communication with the point of attachment (PoA). It is important to know in advance whether or not. Such matters are not considered in the IEEE 802.21 standard under discussion. Therefore, when the standard is in progress, there is a problem that a delay occurs due to a router solicitation message or a router advertisement message in generating an IPv6 address.

It is an object of the present invention to provide an apparatus and method for providing handover information so as to perform efficient handover by transferring information on availability of an IPv6 prefix between an attachment point and a mobile node.

Another object of the present invention is to provide a computer readable recording medium having recorded thereon a program for executing the handover information providing method on a computer.

In order to achieve the above technical problem, a method of providing information for handover from an information server to a mobile node, the capability of a new point of attachment (PoA) to which the mobile node connects from the information server to the mobile node; And transmitting information about the mobile node, wherein the mobile node uses the information about the capabilities of the new connection point to generate an address for use in data communication with the new connection point.

An information server that provides information for handover to a mobile node, wherein the information server transmits information about a capability of a new point of attachment (PoA) to which the mobile node will connect to the mobile node. And a point information transmitter, wherein the mobile node generates an address for use in data communication with the new point of attachment using information about the capability of the new point of attachment.

Hereinafter, an apparatus and method for providing handover information according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating a mobile communication environment according to an embodiment of the present invention. Referring to FIG. 1, a mobile communication environment includes a mobile node (MN) 1, a plurality of connection points PoAs 2 and 3, a correspondent node CN 4, and information servers. Servers: ISs, 5, 6), and multiple networks. Those skilled in the art will appreciate that the network topology shown in FIG. 1 may be configured in various ways.

The mobile node 1 is a mobile terminal using a mobile communication environment. When starting to use mobile communication, the mobile node 1 registers a home address (HoA) with a home agent on a home network. When the mobile node 1 moves to another network, it obtains a care of address (CoA) from a foreign agent (FA) that is an agent on the current network to which the mobile node 1 moves. The mobile node 1 sends the acquired CoA to the home agent for registration. The home agent associates the CoA with the HoA.

In order to transfer data from the corresponding node 4 to the mobile node 1, the corresponding node 4 must know the address of the mobile node 1. Since the correspondent node 4 knows the HoA, it sets the HoA to the destination address and transmits the data. The data set by the HoA as the destination address is received by the home agent. Since the home agent knows the CoA corresponding to the HoA, it sets the CoA to the destination address and transmits the data. It is delivered to the mobile node 1 via the network.

A point of attachment (PoA) connects the mobile node 1 with the network. Examples of the connection point may include an access point (AP), a base station (BS), and the like, but the present invention is not limited thereto. In case of performing data transmission between the mobile node 1 and the network, the connection point (PoA) may be used. Can be

Handover is performed in the process of moving the mobile node 1 to another network. For example, the handover process will be described with reference to FIG. 1. In FIG. 1, an example in which the mobile node 1 performs data communication through the connection point 1 (2) and then moves to an area where data communication is performed through the connection point 2 (3) is illustrated.

The mobile node 1 receives information about the new connection point 2 (3) via the current connection point 1 (2). Information about this connection point 2 (3) may be received from the information servers (5, 6), or directly from the connection point 2 (3). The mobile node 1 can use the received information to know what network protocol the new connection point uses, what services it supports, and prepare for it.

In this handover process, setting of CoA, which is an address to be used by the mobile node 1 in a new network, is very important. In general, setting of an address is performed by receiving a Router Advertisement (RA) message including network information from a connection point and using the same. However, in order to efficiently use the bandwidth of the network, router advertisement messages and the like are transmitted at regular intervals. Therefore, a delay of a certain period (RA delay) occurs for the reception thereof.

In addition, a router solicitation (RS) message requesting to transmit a router advertisement message to a connection point (PoA) may be transmitted. Although the RA delay may be reduced by this RS message, there is still a delay (RS delay) while waiting for the RA message after transmitting the RS message.

IP version 6 supports automatic address generation. IPv6 uses 128-bit addresses. The access point (PoA) transmits the 64-bit network information in the RA message. This is the upper 64 bits of the IPv6 address. The upper 64 bits of an IPv6 address are called an IPv6 prefix. The mobile node 1 uses its own information to generate the lower 64 bits of the IPv6 address. Therefore, the 64-bit network information included in the RA message and the 64-bit address generated by the mobile node 1 are combined to generate an 128-bit IPv6 address, which is called address generation.

However, even when the connection point PoA supports IPv6, it may not support the IPv6 prefix. In this case, since the RA message does not include the IPv6 prefix, the mobile node 1 must generate an address using a method other than automatic address generation. Examples of the method used may include a method using a dynamic host configuration protocol (DHCP), a method using an address preset by a user, and the like. DHCP for generating IPv6 addresses is called DHCP version 6 (DHCPv6). Hereinafter, a method other than automatic address generation, which is used to generate an address when connecting to a connection point (PoA) that does not support IPv6 prefix, is called DHCPv6. Therefore, it will be understood that portions described as DHCPv6 and the like in the following description are not limited to DHCPv6.

If the connection point PoA does not support the IPv6 prefix, if the mobile node 1 can know this in advance, it can prepare to perform DHCPv6 or the like without waiting for an RA message. It also eliminates the need to send RS messages. Therefore, unnecessary RA delay or RS delay can be prevented.

2 is a diagram illustrating a network layer of a mobile node according to an embodiment of the present invention. Referring to FIG. 2, the network layer of the mobile node includes a lower layer 10, a MIH function layer 20, and an upper layer 30.

The lower layer 10 refers to a second layer and a lower layer among the seven layers defined by the Open Systems Interconnection (OSI) reference model, that is, a link layer and a physical layer.

The upper layer 30 is the third and higher layers of the seven layers defined by the OSI reference model, that is, the Internet Protocol (IP) layer, the Mobile IP layer, the transport layer, and the application. Hierarchy, etc.

The MIH functional layer 20 is a layer not defined in the OSI reference model and is a layer defined by the IEEE 802.21 standard. The MIH functional layer 20 is the 2.5th layer between the lower layer 10 and the upper layer 30 and supports handovers in the lower layer 10 and the upper layer 30.

The MIH functional layer 20 supports handover between heterogeneous links independently of the media type of the link to which the mobile node 1 connects. That is, the MIH functional layer 20 supports handover between heterogeneous links independently of the type of the link interface corresponding to the lower layer 10. Referring to FIG. 2, the MIH functional layer 20 may include a media independent event service (MIS) module 22, a media independent information service (MIIS) module 24, and a media independent command service (MIC) module 26. Include.

The MIES module 22 detects the occurrence of an event related to handover between the various links from the mobile node 1 and reports the occurrence of this event to the upper layer 30. More specifically, the MIES module 22 requests the mobile node 1 to register the corresponding node 4 to receive a report of the occurrence of this event, and then the mobile node to which the corresponding node 4 is registered. The occurrence of this event is detected by receiving a message indicating the occurrence of this event from (1).

The MIIS module 24 includes handovers between heterogeneous links by the mobile node 1 from information servers 5, 6 or connection points that collect information about handovers between the heterogeneous links by the mobile node 1. Obtain information about.

The MICS module 26 controls the handover in the lower layer 10, that is, the handover in the link layer, according to a command input from the upper layer 30, for example, a command input by a user.

The handover apparatus and method according to the invention is particularly concerned with the MIIS module 24.

The MIIS module 24 receives a connection point capability information element (POA Capabilities IE), which is information on the capability of the connection point, and determines the network environment through the new connection point (PoA) using this.

FIG. 3 is a diagram illustrating the contents of a POA Capabilities Information Element according to an embodiment of the present invention. Referring to FIG. 3, the connection point capability information element according to the present invention has an IP version 6 field 300 in bit 4 indicating whether the new connection point supports IP version 6. FIG. It also has an IP Version 6 Prefix Available field 310 in bit 5 that indicates whether the IP Version 6 prefix is available at the new connection point.

The MIIS module 24 may determine whether the new connection point supports IP version 6 using the IP version 6 field 300. In addition, the IP version 6 prefix available field 310 may be used to determine whether the IP version 6 prefix is available at the new connection point.

4 is a diagram illustrating a configuration of a handover apparatus according to an embodiment of the present invention. Referring to FIG. 4, the handover apparatus 100 according to the present invention preferably includes a connection point information receiver 110, a connection point capability determiner 120, and an address generator 130.

The connection point information receiver 110 receives information on a new connection point PoA.

The connection point capability determination unit 120 uses the information about the received new connection point (PoA) to determine whether the new connection point (PoA) supports Internet Protocol version 6 (IPv6) and at the new connection point (PoA). Determine whether an IPv6 prefix is available. As already described, the connection point capability determination unit 120 may be implemented in the MIIS module 24. However, it is not limited to this. For example, the connection point capability determination unit 120 may be implemented as a separate module in addition to the MIIS module 24.

The address generator 130 generates an address, that is, a CoA, to be used by the mobile node in data communication with the new connection point PoA.

To this end, an address generation method is determined by whether a new connection point (PoA) supports IPv6 and whether an IPv6 prefix is available at the new connection point (PoA).

If the new point of attachment (PoA) supports IPv6 and the IPv6 prefix is available at the new point of attachment, the CoA is created using the automatic generation of addresses in IPv6.

On the other hand, if a new point of attachment (PoA) supports IPv6 but no IPv6 prefix is available at the new point of attachment, a CoA is generated using DHCPv6 or the like.

5 is a flowchart illustrating each step of the handover method according to an embodiment of the present invention. 5, the handover method performed in the handover apparatus according to the present invention will be described in more detail.

The connection point information receiving unit 110 receives the connection point capability information element to obtain information about the new connection point (S200).

The connection point capability determination unit 120 determines the capability of the new connection point for address generation. First, the connection point capability determination unit 120 refers to bit 4 of the connection point capability information element to determine whether the new connection point supports IPv6 (S210).

 If the new connection point does not support IPv6, the mobile node 1 communicates with the new connection point using IPv4 (S215). Since the communication method using IPv4 is generally performed in the technical field to which the present invention belongs, the description thereof is omitted.

If the new connection point supports IPv6, the connection point capability determination unit 120 determines whether the IPv6 prefix is available at the new connection point (S220).

When the IPv6 prefix is available at the new connection point, the address generator 130 generates CoA using automatic address generation (S230).

To this end, the RA message is received from the new connection point, and the 64-bit IPv6 prefix included in the RA message is combined with the 64-bit sub-address generated by the mobile node to generate a 128-bit IPv6 address.

If the IPv6 prefix is not available at the new connection point, the address generator 130 may not use the IPv6 prefix, that is, use DHCP version 6 (DHCPv6) or use a preset address. CoA is generated by using (S240).

In this way, whether the IPv6 prefix is available at the new connection point can be known in advance before receiving the RA message through the connection point capability information element, so that it is possible to prepare in advance for DHCP version 6 and the like that do not use the IPv6 prefix, Unnecessary transmission of RS messages can be prevented. There is no need to wait for an RA message and no need to send an RS message, thus avoiding unnecessary delay on handover. In addition, since unnecessary RS message transmission is prevented, the bandwidth of the network due to handover can be efficiently used.

The present invention can be embodied as code that can be read by a computer (including all devices having an information processing function) in a computer-readable recording medium. The computer-readable recording medium includes all kinds of recording devices in which data that can be read by a computer system is stored. Examples of computer-readable recording devices include ROM, RAM, CD-ROM, magnetic tape, floppy disks, optical data storage devices, and the like.

Although the foregoing description has been focused on the novel features of the invention as applied to various embodiments, those skilled in the art will appreciate that the apparatus and method described above without departing from the scope of the invention. It will be understood that various deletions, substitutions, and changes in form and detail of the invention are possible. Accordingly, the scope of the invention is defined by the appended claims rather than in the foregoing description. All modifications within the scope of equivalents of the claims are to be embraced within the scope of the present invention.

According to the apparatus and method for providing handover information according to the present invention, it is possible to prepare in advance for DHCP version 6 or the like, since the mobile node can know in advance whether to receive the IPv6 prefix at the new connection point before receiving the RA message. It is possible to prevent unnecessary transmission of RS messages. Therefore, unnecessary delay on the handover can be prevented, and the bandwidth of the network due to the handover can be effectively used.

Claims (10)

In the method for providing information for handover from the information server to the mobile node, Sending information from the information server to the mobile node about the capability of a new point of attachment (PoA) to which the mobile node will connect, The mobile node uses the information on the capabilities of the new connection point to determine whether an Internet Protocol version 6 (IPv6) prefix is available at the new connection point and whether an IPv6 prefix is available. And generating an address to be used in data communication with the new connection point according to the method determined by the method. The method of claim 1, wherein transmitting information about the capability of the new connection point comprises: And transmitting a PoA Capabilities Information Element (PoA Capability Information Element) including information about the capabilities of the new connection point. The method of claim 2, wherein the connection point capability information element is: A type field indicating that the information element is a connection point capability information element; A length field indicating a length of information included in the information element; And And a value field representing information on the capability of the new connection point in the form of a bitmap. The method of claim 3, wherein the value (value) field, And a bit 5 having an IP version 6 Prefix Available field indicating whether an Internet Protocol version 6 (IPv6) prefix is available at the new connection point. The method of claim 1, wherein transmitting information about the capabilities of the new connection point comprises: Sending, at the information server, information about the capabilities of the new connection point to a Media Independent Information Service (MIIS) module included in a Media Independent Handover (MIH) functional layer of the mobile node. Handover information providing method, characterized in that. An information server for providing information for handover to a mobile node, A connection point information transmitter for transmitting information on a capability of a new point of attachment (PoA) to which the mobile node will connect; The mobile node uses the information on the capabilities of the new connection point to determine whether an Internet Protocol version 6 (IPv6) prefix is available at the new connection point and whether an IPv6 prefix is available. And generate an address for use in data communication with the new connection point in accordance with the manner determined by the method. The method of claim 6, wherein the connection point information transmission unit, And a PoA Capabilities Information Element (PoA Capability Information Element) containing information about the capabilities of the new connection point. 8. The method of claim 7, wherein the connection point capability information element is: A type field indicating that the information element is a connection point capability information element; A length field indicating a length of information included in the information element; And And a value field representing information about the capability of the new connection point in the form of a bitmap. The method of claim 8, wherein the value (value) field, And at bit 5 an IP version 6 Prefix Available field indicating whether an Internet Protocol version 6 (IPv6) prefix is available at the new connection point. 10. The method of claim 6, wherein the connection point information transmission unit, And an information server for transmitting information about the capability of the new connection point to a MIIS module included in a media independent handover (MIH) functional layer of the mobile node.

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