KR100687748B1 - Method and System for Fast Handover being independent of Mobile Node - Google Patents

Abstract

The present invention enables fast handover by implementing a fast handover function only on a network side without implementing a fast handover function in a mobile terminal when implementing fast handover for providing a real-time service in a mobile IPv6 supporting network. To a method and system. To this end, upon receiving the data link layer handover signal from the router where the mobile terminal is currently located, the mobile station sends a message indicating the start of handover to the router to which the mobile terminal is to move, and the router to which the mobile terminal is to move is located in the mobile terminal. Sends a message indicating that a message indicating the start of a handover has been received to the router, and when the router to which the mobile terminal intends to move receives a link up trigger signal indicating that a link to the mobile terminal has been formed in the data link layer Router Advertisement Message And forward the forwarded packet.

Fast Handover, Mobile IPv6

Description

Method and system for performing fast handover independent of mobile terminal {Method and System for Fast Handover being independent of Mobile Node}

1 illustrates a conventional handover process.

2 illustrates a network structure assumed in a preferred embodiment of the present invention.

3 illustrates a basic procedure of fast handover proposed in the preferred embodiment of the present invention.

4 illustrates the functions of a router where a mobile terminal is currently located and a router to which the mobile terminal is to move.

The present invention provides a fast handover support by implementing a fast handover function only on a network side without implementing a fast handover function in a mobile terminal when implementing a fast handover for providing a real-time service in a mobile IPv6 supporting network. It relates to structures and procedures.

Mobile IPv6 is a representative protocol for supporting mobility of UE in IPv6 network. Mobile IPv6 maintains service continuity for a mobile terminal by updating binding information for a home agent (HA) and a counterpart node whenever a subnet is changed.

However, in case of Mobile IPv6, there is a problem that it may be difficult to support real-time service due to delay in moving detection and new registration when changing subnet. In order to solve such a problem and to smoothly provide a real-time service such as VoIP, which must be supported in the next generation internet, various technologies for supporting fast handover for real-time service support in Mobile IPv6 have been proposed.

FMIPv6 [R. Koodli, et al., "Fast Handovers for Mobile IPv6," IETF I-D draft-ietf-mipshop-fast-mipv6-03, October 2004.] is a representative technique for supporting fast handover in Mobile IPv6.

FMIPv6 uses a trigger on the data link layer to pre-generate the care of address (CoA) on the new subnet and to use a two-way IP tunnel between the previous router (PAR) and the new router (NAR). Fast handover.

Note that FMIPv6 basically assumes the mobile terminal's participation in the handover procedure. That is, in FMIPv6, the mobile terminal should be aware of the trigger of the link layer and use this to perform router advertisement request for PAR, new CoA preconfiguration, prebinding request for PAR, and fast neighbor node advertisement procedure in NAR.

However, in FMIPv6, when a network operator wants to implement fast handover in a network, there is a problem that it is economically or practically difficult to implement a fast handover function in all terminals.

In the present invention, to solve the above problems, to improve the FMIPv6 to operate independently of the mobile terminal to support fast handover using only the network function in FMIPv6.

In a preferred embodiment of the present invention, a fast handover system independent of a mobile terminal is a data link layer handover in an Internet network including a home agent managing an address of the mobile terminal and a counterpart node communicating with the mobile terminal. When a signal is received, a message indicating a start of handover (HI) is transmitted, and when a message indicating a reception of a message indicating a start of handover (HI) is received (HACK), a packet directed to a mobile terminal is transmitted. A first router; Upon receiving a message indicating the start of a handover (HI) from the first router, sending a message indicating the start of the handover (HI) and indicating that a link to the mobile terminal is established at the data link layer And a second router configured to transmit a Router Advertisement (RA) message and a packet transmitted from the first router to the mobile terminal upon receiving a link up trigger signal.

In a preferred embodiment of the present invention, a router is a handover triggered by reception of a data link layer handover signal in an Internet network including a home agent managing an address of a mobile terminal and a counterpart node communicating with the mobile terminal. Receiving a HI message indicating a start of a handover transmits a HACK message indicating that a HI message has been received indicating that a handover has been initiated and directed to the mobile terminal until a connection is established with the mobile terminal. Receives and buffers packets and receives a Router Advertisement (RA) message to the mobile terminal upon receiving a link up (LU) trigger signal indicating that a link to the mobile terminal has been formed at the data link layer. And a router for transmitting the buffered packet.

In addition, a fast handover system independent of the mobile terminal forms a two-way IP tunnel with a router (PAR) that has sent a (HI) message indicating the start of a handover triggered by the reception of a data link layer handover signal, The router is characterized in that the endpoint of the two-way IP tunnel.

In another preferred embodiment of the present invention, a method for implementing a fast handover independent of a mobile terminal is provided in an Internet network including a home agent managing an address of a mobile terminal and a counterpart node communicating with the mobile terminal. A method for implementing an independent handover to a mobile terminal, wherein when the mobile terminal receives a data link layer handover signal from a router (PAR) in which the mobile terminal is currently located, the mobile terminal indicates the start of handover to the router (NAR) to which the mobile terminal is to move. Sending an HI message; Transmitting (HACK) a message indicating that a router (NAR) to which the mobile terminal intends to move has received a HI message indicating the start of the handover (HI) to a router (PAR) in which the mobile terminal is currently located; Forwarding a packet destined for the mobile terminal to a router (NAR) to which the mobile terminal is to move in a router (PAR) in which the mobile terminal is currently located; and a router (NAR) to which the mobile terminal is to be moved at the data link layer. A Router Advertisement message is sent to the mobile terminal upon receiving a link up trigger signal indicating that a link to the mobile terminal has been established. And transmitting the forwarded packet.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the same elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In the present invention, in order to support handover to a mobile node, it is assumed that Mobile IPv6 and OPDD (Optimistic Duplicate Address Detection) are implemented first.

In the conventional fast handovers for mobile IPv6 (FMIPv6), when a mobile terminal moves to a new access router (NAR) area during handover, 1) the movement of the L3 layer is recognized (movement detection process) and 2) a new CoA address is provided. 3) The newly created CoA address must be registered in the other node communicating with the home agent or the mobile terminal (Binding Update process).

In the present invention, although basically following the approach implemented in the conventional FMIPv6, the following differences exist in each process.

1. Movement Detection Process

In the present invention, a motion detection process uses the same method as FMIPv6. That is, the mobile terminal needs a trigger (Pre-handover, PRE-HO) of the data link layer to move from the PAR to the NAR and a link up trigger (LU) indicating that a new link is established in the NAR. Accordingly, the present invention assumes that the system supports the PRE-HO trigger signal and the LU trigger signal. In the present invention, the network knows the trigger signal, but the mobile terminal does not know the trigger signal.

2. New CoA Configuration Process

In FMIPv6, if the L3 layer moves (movement between access routers using different prefixes) during the movement detection process, the mobile terminal should prepare to create a new CoA. However, unlike FMIPv6, it does not support a new CoA formation process to support handover independent of the mobile terminal.

3. Binding Update process

In FMIPv6, two-way tunnels are used to prevent blocking or disconnection of services during binding updates. In the present invention, although the two-way tunnel is used, the HI / HACK message used in the two-way tunnel of the present invention is used only to transfer information of the mobile terminal and form a tunnel, which was used in the conventional FMIPv6. This is different from the function of the / HACK message.

Based on the above-described differences, this application will describe a system and method for performing handover independently of a mobile terminal.

1 illustrates a handover process in the conventional FMIPv6.

The mobile terminal 100 exchanges a message with a router (hereinafter, referred to as PAR) 110 where the mobile terminal is currently located in order to obtain information about a router (hereinafter referred to as NAR) 120 to which the mobile terminal is to move, and includes in the message. Create NCoA to use from Prefix information and send NCoA to PAR in FBU message to verify its validity.

The PAR 110 sends a HI message to the NAR 120 for the NCoA validity check on behalf of the mobile terminal 100 and receives a HAck, which is a response message. The FBack message is sent to notify the mobile station of the validity.

When the mobile terminal leaves the PAR link due to the movement of the mobile terminal, the PAR 110 forwards the packet to be delivered to the mobile terminal to the NAR 120 through forwarding. When the mobile terminal receives the FBack and enters the NAR link, it transmits the FNA to the NAR 120 to inform its own connection and quickly receive the packet delivered to the mobile terminal.

2 illustrates a network structure assumed in a preferred embodiment of the present invention.

In the Internet network 210, which is composed of a home agent 214 managing an address of a mobile terminal and a counterpart node 215 communicating with the mobile terminal, the PAR 211 may determine a router where the mobile terminal 213 is currently located. NAR 212 represents the router to which the mobile terminal 213 is to move.

In FIG. 2, the mobile terminal 213 is initially located in the PAR 211 and then moves to the NAR 212, and needs handover support for real-time service provision at this moment of movement. At this time, the mobile terminal basically uses Mobile IPv6 and ODAD [N. Moore, "Optimistic Duplicate Address Detection for IPv6, IETF I-D draft-ietf-ipv6-optimistic-dad-05, February 2005".

3 illustrates a basic procedure of fast handover proposed in the preferred embodiment of the present invention.

The PAR receives a trigger (Pre-handover, PRE-HO) of the data link layer that the mobile terminal tries to move from the PAR to the NAR (S300). This data link layer trigger includes link layer information (eg, MAC address) of the mobile terminal and the NAR. It is assumed that network side such as PAR and NAR are aware of such data link layer trigger, but mobile terminal does not know about such data link layer trigger.

In the conventional FMIPv6, an HI message indicating the start of handover is triggered by a fast binding update (F-BU) message from a mobile terminal and used to verify a pre-formed CoA (see FIG. 1).

However, in the present invention, the HI (Handover Initiate) message indicating the start of the handover is sent to the NAR when the PAR receives a trigger of the data link layer (Pre-handover, PRE-HO) that the mobile terminal tries to move from the PAR to the NAR. It is transmitted and used for forming a bidirectional IP tunnel between the PAR and the NAR (S310).

The NAR that received the HI message Respond to the PAR with a HACK (Handover ACK) message indicating that the message indicating the start of the handover (HI) has been received (S320). This HACK message informs the result of the two-way IP tunnel formation. If the tunnel formation is successful, the NAR forms an entry to process the packet routed to the previous CoA of the mobile terminal. At this time, both end points of the bidirectional tunnel are PAR and NAR.

In the conventional FMIPv6, although the tunnel endpoint is NCoA in the NAR, in the present invention, since NCoA is not formed in advance, the endpoint of the bidirectional IP tunnel should be NAR, unlike in FMIPv6.

The HI message used in the present invention is identical to the HI message used in FMIPv6 except for a code value. The HI message used in the present invention newly defines the case of the code value 2 in addition to the code values 0 and 1 of the conventional HI to inform the PAR of the NAR.

code

0: Code value when the PAR processes an FBU whose source IP address is PCoA

1: Code value when the PAR processes an FBU whose source IP address is not PCoA

2: Code value when implementing the handover method of the present invention

In addition, the two flags are set as follows.

Two flags

S : Since the HI message of the present invention does not contain NCoA, this flag should be set to zero.

U : This flag should be set to 1 to buffer packets destined for the NAR to the mobile terminal.

In addition, the HACK message used in the present invention is the same as the HACK message used in FMIPv6. However, in the conventional HI / HACK message, the option required for new CoA verification should be set to be inactive.

When the bidirectional IP tunnel is formed after receiving the HACK message, the PAR forwards the packet destined for the mobile terminal to the NAR immediately after receiving the HACK message, and the NAR buffers it until a connection with the mobile terminal is established (S330).

When the mobile terminal moves to the NAR, the NAR receives a link up (LU) trigger from the link layer indicating that a link to the mobile terminal is established. This LU trigger includes link layer information of the mobile terminal (S340).

In FMIPv6, it can be seen that the link to the mobile terminal is formed by the FNA message from the mobile terminal (see FIG. 1). However, in the present invention, the NAR can recognize that the link to the mobile terminal is formed through the LU trigger. The NAR delivers the fast router advertisement and the buffered packet to the mobile terminal even when the NAR is not requested to receive the router advertisement from the mobile terminal (S350).

That is, the NAR receiving the LU trigger (S340) immediately sends a unicast router advertisement message to the mobile terminal and simultaneously transmits the buffered packet (S350) . In this case, the use of unicast instead of general multicast in router advertisements is to reduce the use of radio resources. If a radio section already has a channel for multicast, multicast may be used.

The mobile terminal performs the fast CoA generation procedure defined in the ODAD using the received router advertisement information (360). This fast router advertisement and ODAD procedure is intended to enable fast CoA generation without the involvement of a mobile terminal.

When a new CoA is formed, the mobile terminal performs a binding update procedure using the mobile terminal (370). Until the binding update is completed, packet transmission and reception with the counterpart node of the mobile terminal is performed by a bidirectional tunnel between the PAR and the NAR.

4 illustrates the functions of a router where a mobile terminal is currently located and a router to which the mobile terminal is to move.

The link layer interworking unit 411 of the PAR 410 receives a link layer trigger PRE-HO that the mobile terminal 430 tries to move from the PAR to the NAR from the data link. When the PAR receives the PRE-HO, the transmitting / receiving unit 412 of the PAR transmits a HI message indicating the start of handover (HI) to the NAR 420, and the transmitting / receiving unit 421 of the NAR 420 transmits the hand. After receiving the HI message indicating the start of over (HI), the PAR 410 transmits a HACK message indicating that it has received the HI message indicating the start of handover (HI).

When a bidirectional tunnel is formed between the PAR 410 and the NAR 420, the transfer unit 413 forwards the packet destined for the mobile terminal 430 to the NAR 420. The buffer 422 on the NAR side buffers the packet forwarded by the PAR until the connection with the mobile terminal 430 is established, and then links up to indicate that a link to the mobile terminal 430 is formed in the data link layer. When receiving the (LU) trigger signal, the mobile station 430 transmits a router advertisement message and the buffered packet.

The invention can also be embodied as computer readable code on a computer readable recording medium. Computer-readable recording media include all kinds of recording devices that store data that can be read by a computer system. Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage, and the like, which are also implemented in the form of carrier waves (for example, transmission over the Internet). It also includes. The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

The best embodiments have been disclosed in the drawings and specification above. Although specific terms have been used herein, they are used only for the purpose of describing the present invention and are not used to limit the scope of the present invention as defined in the meaning or claims.

Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

According to the present invention, even when the fast handover function is not implemented in the mobile terminal, the fast handover support for the mobile terminal in the network may occur.

According to the present invention, an independent handover is supported by a mobile router using fast router advertisement and OP-DAD without preconfiguring an address. Independent operation is possible and the procedure is simplified.

Claims (11)

In the Internet network consisting of a home agent for managing the address of the mobile terminal and a partner node communicating with the mobile terminal, Receiving a data link layer handover signal (PRE-HO) sends a message indicating the start of a handover (HI) and a message indicating that a message indicating the start of the handover (HI) has been received (HACK) A first router for transmitting a packet destined for the mobile terminal upon receipt of the signal; When receiving a message indicating the start of the handover (HI) from the first router, sending a (HACK) message to the first router indicating that the message indicating the start of the handover (HI) has been received and And receiving a link up (LU) trigger signal indicating that a link to the mobile terminal is established at the data link layer, sending a router advertisement (RA) message to the mobile terminal and a packet transmitted from the first router to the mobile terminal. And a second router transmitting the fast handover system independent of the mobile terminal. The method of claim 1, wherein the data link layer handover signal is And a data link layer information of the mobile terminal and the second router. The method of claim 1, wherein the link up (LU) trigger signal is Fast handover system independent of the mobile terminal, characterized in that it comprises data link layer information of the mobile terminal. In the Internet network consisting of a home agent for managing the address of the mobile terminal and a partner node communicating with the mobile terminal, Receiving a message indicating the start of a handover (HI) triggered by the reception of a data link layer handover signal, transmitting and receiving transmitting a (HACK) message indicating that a message indicating the start of the handover (HI) has been received. part; A buffer for receiving and buffering packets destined for the mobile terminal until a connection with the mobile terminal is established; A Router Advertisement message is sent to the mobile terminal upon receiving a link up trigger signal indicating that a link to the mobile terminal has been established at the data link layer. And a link layer interworking unit for transmitting the buffered packet. 5. The method of claim 4, wherein the data link layer handover signal is And a data link layer information of the mobile station and a router (NAR) to which the mobile terminal is to move. The method of claim 4, wherein the link up (LU) trigger signal is Router comprising the data link layer information of the mobile terminal. 5. The router of claim 4 wherein the router is Form a two-way IP tunnel with a router (PAR) that has sent a message indicating the start of a handover (HI) triggered by receipt of a data link layer handover signal, wherein the router is an endpoint of the two-way IP tunnel; Router. A method for implementing an independent handover in a mobile terminal in an Internet network including a home agent managing an address of a mobile terminal and a counterpart node communicating with the mobile terminal, When the mobile terminal receives a data link layer handover signal from a router (PAR) in which the mobile terminal is currently located, transmitting a HI message indicating an initiation of handover to the router NAR to which the mobile terminal is to move; Transmitting (HACK) a message indicating that a router (NAR) to which the mobile terminal intends to move has received a HI message indicating the start of the handover (HI) to a router (PAR) in which the mobile terminal is currently located; Forwarding a packet destined for the mobile terminal from a router (PAR) in which the mobile terminal is currently located to a router (NAR) to which the mobile terminal is to move; and When a router (NAR) to which the mobile terminal intends to move receives a link up (LU) trigger signal indicating that a link to the mobile terminal is formed in the data link layer, a Router Advertisement message is sent to the mobile terminal. And transmitting the forwarded packet. 9. The method of claim 8, wherein the data link layer handover signal is And a data link layer information of the mobile station and a router (NAR) to which the mobile terminal is to move. The method of claim 9, wherein the link up (LU) trigger signal is Method for implementing a fast handover independent of the mobile terminal, characterized in that it comprises data link layer information of the mobile terminal. The method of claim 8, The router (PAR) in which the mobile terminal is currently located and the router (NAR) to which the mobile terminal is to move form a bidirectional IP tunnel, and the router (NAR) to which the mobile terminal is to move is an endpoint of the bidirectional IP tunnel. A method for implementing fast handover independent of the mobile terminal.

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