KR20090054146A - System, apparatus and method for performing fast mobile ipv6 handover - Google Patents

Abstract

The present invention relates to a fast mobile IPv6 handover system, apparatus and method.

The present invention provides a novel CoA configuration and address duplication method for fast handover in a high speed mobile IPv6 network.

The present invention seeks to minimize packet loss and session dropout that can occur during handover by minimizing handover delay when the mobile station moves between different subnets.

The present invention can be expected to reduce the handover delay time due to fast address generation and address duplication check.

FMIPv6, MIPv6, Address Duplicate Check, CoA Setting, Move Detection, Handover

Description

High Speed Mobile IPv6 Handover System, Apparatus and Method for Performing Fast Mobile IPv6 Handover}

The present invention relates to a fast mobile IPv6 handover method, and more particularly, to a handover system, apparatus and method for fast handover in a fast mobile IPv6 network.

The Internet, in which fixed hosts are connected to wired networks, is evolving to support mobile nodes in which wired and wireless networks interoperate with each other.

The protocol developed to support the mobility of the terminal is mobile IP. The Mobile IP Working Group has proposed the Mobile IPv6 (MIPv6) protocol to support mobility of terminals in the IPv6 network layer.

Mobile IPv6 technology works transparently to protocols above the IP layer, and allows for mobility of IPv6 hosts without interruption of active Transmission Control Protocol (TCP) connections and User Datagram Protocol (UDP) port bindings. Technology to provide.

1 is a diagram illustrating a conventional mobile IPv6 handover procedure.

When the mobile terminal 100 moves to a new subnetwork, the mobile terminal 100 performs L2 handover with a new access point (NAP) 300 (S10). Subsequently, the mobile terminal 100 generates a router request message (Router Solicitation) requesting the prefix information of the new access router 320 and transmits it to the new access router 320 (S12). From the new access router 320, Receive a router advertisement message (Router Advertisement) transmitted (S14).

The mobile terminal 100 may detect the movement by periodically receiving a router advertisement message from the new access router 320 whenever the mobile terminal 100 moves to the new subnetwork.

After receiving the router advertisement message including the prefix information from the new access router 320, the mobile terminal 100 sets a new care of address (hereinafter referred to as 'nCoA') address setting process and duplicates the address (Duplicate). Address Detection: DAD) is started (S16). In general, the mobile terminal 100 and the access router must wait for a certain time before transmitting the router request message and the router advertisement message, respectively, and then start the transmission. This is to prevent large numbers of access routers from sending messages at exactly the same time.

In addition, the mobile terminal 100 may not start the handover process for at least 1000 ms for address duplication to generate nCoA.

Therefore, the mobile terminal 100 spends a great deal of time in the mobile detection process, address generation and address duplication detection that occur during the movement of the surrounding subnetwork.

That is, since the mobile terminal 100 must repeatedly process the movement detection process, address generation, and address duplication detection process when the subnetwork moves, the total handover delay time increases.

In order to solve the handover problem of mobile IPv6, a fast handover for mobile IPv6 (hereinafter referred to as FMIPv6) scheme has been proposed.

The FMIPv6 protocol is a technique for proactively acquiring CoA from a cell that will detect handover and move quickly through the support of the link layer. In other words, it grasps information about a new location to move before handover and processes it in advance so that service can be quickly resumed if a move actually occurs.

2 is a diagram illustrating a conventional procedure for performing FMIPv6 handover.

When the mobile terminal 100 detects an access point (New Access Point, hereinafter referred to as 'NAP') 300 of a new sub-network, a new access router (hereinafter referred to as 'NAR') 320 Router for proxy to previous Access Router (hereinafter referred to as 'PAR') 220 of the network currently being serviced to obtain the information (optional, terminal information of the NAR 320, router information, etc.). A request message (Router Solicitaion for Proxy: RtSolPr) is generated and transmitted (S20). In other words, when receiving the L2 trigger information, the mobile terminal 100 informs the PAR 220 that it will move from the access point currently connected to the PAR 220 to the access point connected to the NAR 320.

When the mobile terminal 100 transmits a router request message for proxying to the PAR 220, it starts L3 handover.

When the PAR 220 receives the router request message for proxy from the mobile terminal 100, the PAR 220 generates a proxy router advertisement message (PrRtAdv) and transmits it to the mobile terminal 100 (S22).

The mobile terminal 100 sets the nCoA address of the mobile terminal 100 using the received L2 trigger information (prefix, address of the NAR 320). The mobile terminal 100 generates a fast binding update message (Fast-BU) including information of the mobile terminal 100 and the NAR 320 in order to perform packet buffering and address duplication check. To transmit (S24).

When the PAR 220 receives the fast binding update message, the PAR 220 starts buffering the packet received from the target node (CN) 500, checks the nCoA address duplication of the mobile terminal 100, and checks the PAR 220 and the NAR. In order to establish a bidirectional tunnel between the 320, a handover start message (Handover Initiate HI) is generated and transmitted to the NAR 320 (S26).

When the NAR 320 receives the handover start message from the PAR 220, the NAR 320 starts the address duplication check for the nCoA of the mobile terminal 100 (S28).

However, the NAR 320 has to delay the handover procedure for a predetermined time (1000 ms) to check for address duplication. Therefore, the mobile terminal 100 has a problem that it is not possible to start the handover process for communication for a certain time.

In addition, the PAR 220 stores packets received from the target node 500 before transmitting the handover start message, and after completing the address duplication check process in the PAR 220, a handover acknowledgment message (Hackover Acknowledge: Hack). Continue to store the packet until it is received. Therefore, in the PAR 220, when a large number of bulk data is received, there is a problem in that packet overflow occurs in the queue of the PAR 220 to generate packet loss and network load.

In order to solve such a problem, the present invention is to provide a new CoA configuration and address duplication method for fast handover in a high-speed mobile IPv6 network.

A high-speed mobile IPv6 handover method according to an aspect of the present invention for achieving the technical problem, (a) a new handover start message from the previous access router to which the mobile terminal is connected through a previous access point-the new hand Receiving an over start message comprising a flag of address duplication check request bits for applying advanced lookup techniques to the new Care of Address address duplication check of the mobile station; (b) performing a fast address duplication check by performing a lookup technique applied to a Patricia Trie technique to a neighbor cache when the flag among the reservation flags of the received new handover start message exists; And (c) after performing the fast address duplication check, a new handover acknowledgment message in response to the new handover start message, wherein the new handover acknowledgment message includes a new care of address address duplication check response option. Generating and transmitting to the previous access router.

According to an aspect of the present invention, a high-speed mobile IPv6 handover system includes a new hand for performing L2 handover with the mobile station and performing packet tunneling and new care of address address duplication of the mobile station. Generate and send an over start message, the new handover start message including a flag of address duplication check request bits for applying advanced lookup techniques to the new care of address address duplication check; An old access router receiving a new handover grant message in response to the handover start message; And when the flag of the reservation flag of the new handover start message received from the previous access router is present, performs a lookup technique applied to the Patricia Trie technique to the neighbor cache, and duplicates a new care of address address. And a new access router that generates the new handover grant message including a check response option and sends it to the previous access router.

According to an aspect of the present invention, a high-speed mobile IPv6 handover apparatus includes a new care of address address duplication check of a mobile terminal from a previous access router to which the mobile terminal is connected through an access point, and the previous access router. A message receiver for receiving a new handover initiation message (NHI) for establishing a bidirectional tunnel between the new access routers; When there is a flag including a new care-of-address duplicate address check request bit in the reserved field of the new handover start message, a fast address duplication checker that performs a lookup technique applied to the Patricia Trie method to the NAVER cache. ; And a message transmitter configured to generate a new handover acknowledgment message including a new care of address address duplication check response option in response to the new handover start message, and transmit it to the previous access router.

By the above-described configuration, the present invention can be expected to reduce the packet loss and network load by minimizing the handover time that occurs when the mobile station moves between subnets.

The present invention can be expected to have an effect that can be detected faster when performing the handover than the conventional handover method.

The present invention can be expected to reduce the handover delay time due to fast address generation and address duplication check.

The present invention can be expected to reduce the network load due to reduced packet overflow in the router buffer.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification.

Throughout the specification, when a part is said to "include" a certain component, it means that it can further include other components, without excluding other components unless specifically stated otherwise. In addition, the terms “… unit”, “… unit”, “module”, “block”, etc. described in the specification mean a unit that processes at least one function or operation, which is hardware or software or a combination of hardware and software. It can be implemented as.

3 is a diagram schematically showing the configuration of the FMIPv6 handover system according to an embodiment of the present invention.

The FMIPv6 handover system according to an embodiment of the present invention includes a PAR 220, a NAP 300, and a NAR 320.

The PAR 220 is a device providing services in the mobile terminal 100 and the current serving network, and receives information of an access router to move from the mobile terminal 100 when the mobile terminal 100 moves to a different subnet. Then, it is connected to the access router to move and performs a series of processes to perform address duplication of nCoA.

The NAP 300 is an access point of a subnet to which the mobile terminal 100 will move, and periodically transmits information of an access router connected to the access point to the mobile terminal 100.

The NAR 320 minimizes handover time by performing an address duplication check for generating nCoA of the mobile terminal 100 using the advanced lookup technique proposed by the present invention. Next, an internal configuration of the FMIPv6 handover device will be described in detail with reference to FIG. 4.

4 is a block diagram schematically showing the internal configuration of the FMIPv6 handover apparatus according to an embodiment of the present invention.

Here, the handover device refers to an access router, and in the embodiment of the present invention, refers to the NAR 320.

The FMIPv6 handover apparatus 320 according to an embodiment of the present invention includes a message receiver 322, a fast address duplication checker 324, and a message transmitter 326.

The message receiving unit 322 is a new handover initiation message (NHI) for the nCoA address duplication check of the mobile terminal 100 from the PAR 220 and the bidirectional tunnel establishment between the PAR 220 and the NAR 320. Receive

The fast address duplication checker 324 performs a lookup using the Patricia Trie technique when there is an nCoA address redundancy check (DAD) request bit defined by a 1-bit D flag in a reserved field of a new handover start message. Fast address redundancy checks are performed by performing techniques to the neighbor cache. Hereinafter, a new handover start message will be described in detail with reference to FIG. 5.

Upon completion of the fast address duplication check, the message transmitter 326 generates a new handover acknowledgment message including a new Care of Address Duplicate Check response option and transmits it to the PAR 220 in a unicast manner. Hereinafter, a new handover approval message will be described in detail with reference to FIG. 6.

5 is a diagram illustrating a format of a new handover start message according to an embodiment of the present invention.

The format of the new handover start message according to the embodiment of the present invention is configured by adding the nCoA address redundancy check request bit defined by the D flag 600 of 1 bit among the reserved flags in the conventional handover start message.

In addition, the new handover start message includes the previous MN's CoA (CoA) of the previous mobile terminal 100 and the previous AR's global address using the 1 bit of the option field 620. Here, the added option field 620 is used to tunnel the PAR 220 and NAR 320 and to use the advanced lookup technique described below.

In addition, the new handover start message includes various terminal information such as nCoA of the mobile terminal 100 and an address of the NAR 320 as a basic option, and router information.

6 illustrates a format of a new handover approval message according to an embodiment of the present invention.

The format of the new handover acknowledgment message according to an embodiment of the present invention is to add a two bit F-flag 700 of one of the reserved flags in the conventional Handover Acknowledge (HA) message. Configure.

The 2-bit F-flag 700 of the new handover grant message is shown in Table 1 below.

Here, '00' indicates that the MAC address copied to the neighbor cache is not available, and '01' indicates that the link local address and nCoA are allocated, that is, the address generated by the mobile terminal 100 successfully. In this case, '10' indicates a substitute address which is not used, but does not use an address generated by the mobile terminal 100, and a link local address needs to be changed, and '11' indicates a mobile terminal (100). ) Means that the generated address is incorrect.

In addition, the new handover approval message includes an added option field 720 including 'New MAC address', 'New link-local address', and 'NCoA DAD reply option'. Here, the 'NCoA DAD reply option' includes table information of the F-flag 700 shown in [Table 1].

Next, a method of performing FMIPv6 handover will be described in detail with reference to FIG. 7.

7 is a view for explaining a method for performing FMIPv6 handover according to an embodiment of the present invention.

The NAR 320 periodically transmits a router advertisement message including the prefix information to the NAP 300.

The NAP 300 extracts and stores the prefix information from the router advertisement message received from the NAR 320, and stores the stored router advertisement (SRA) including its ID and the prefix information of the NAR 320. It generates a message and broadcasts periodically (S100). In this case, the SRA message is a message transmitted to the mobile terminal 100 to quickly proceed with the L3 handover during the L2 handover.

When receiving the SRA message, the mobile terminal 100 generates and transmits a router request message for the proxy to the PAR 220 currently receiving the service in order to obtain information of the NAR 320 (S102). In step S104, a proxy router advertisement message is received from the PAR 220. In other words, when receiving the SRA message, the mobile terminal 100 informs the PAR 220 that it will move from the access point currently connected to the PAR 220 to the access point connected to the NAR 320. Here, the router request message for proxy includes the L2 ID of the NAP 300 to which the mobile terminal 100 moves. The PAR 220 then begins to map the received L2 ID to connect to the NAR 320.

The mobile terminal 100 compares the prefix information of the NAR 320 with the existing prefix information previously stored in the memory based on the SRA message and the proxy router advertisement message.

When the prefix information of the NAR 320 and the previously stored existing prefix information are different, the mobile station 100 performs nCoA address setting by using a stateless address auto configuration (SAA) method.

Subsequently, the mobile terminal 100 generates a fast binding update message (Fast-BU) including nCoA and transmits it to the PAR 220 (S106). Here, the fast binding update message includes nCoA, Home of Address (HoA), life time, address of NAR 320, etc. of the mobile terminal 100.

When the PAR 220 receives the fast binding update message, the PAR 220 starts buffering the packet received from the target node 500, and checks the nCoA address duplication of the mobile terminal 100 and between the PAR 220 and the NAR 320. A new handover initiation message (NHI) is generated and transmitted to the NAR 320 for bidirectional tunnel establishment at step S108.

The NAR 320 analyzes the received new handover start message and, when there is a D flag (nCoA DAD Request Bit) in the new handover start message format, uses a lookup technique that applies the Patricia Trie technique to NAVER cache. It performs on (Neighbor Cache) (S110). This has the effect of performing a fast address redundancy check. Here, the neighbor cache includes the access router information of the NAR 320 and the mobile terminal information connected to each access router.

The aforementioned Patricia Tree technique is well known and will not be described in detail.

In the Patricia tree inspection, the address lookup delay time t _LD required for MAC address checking and address duplication checking of the mobile terminal 100 is expressed by Equation 1 below.

t _LD = t _DAC × N

Here, t _DAC is a delay time for delay processing and comparison in RAM, and N is a lookup number in the Patricia tree check.

Current DRAMs require about 60 to 100 nsec to process memory and 10 nsec time for comparison. That is, t _DAC can be set to a value of 70 to 110 nsec.

In the Patricia tree inspection, the lookup processing time is required 48 times the processing memory. Therefore, N can be seen as 48.

As a result, the total time t _LD required to handle the address duplication check is calculated from Equation 1 from 3.36 μsec to 5.28 μsec.

In other words, it can be seen that the address duplication check time has a very small delay time compared to 1000 msec which is required in the conventional address duplication check.

8 illustrates a delay time taken for the average address duplication check when the address duplication check method proposed in the present invention is applied.

As shown in FIG. 8, the address duplication checking method proposed by the present invention is measured using a traffic intensity value to view the stability of the system in various situations. It shows good performance.

After performing the address duplication check process, the NAR 320 generates a new handover acknowledgment (NHA) message corresponding to the new handover start message and transmits it to the PAR 220 through a unicast method ( S112).

After receiving the new handover acknowledgment message from the NAR 320, the PAR 220 includes the 'NCoA DAD reply option' of the new handover acknowledgment message in the fast-back message and the mobile terminal 100 and the NAR 320. S114 and S116 are transmitted.

The mobile terminal 100 and the NAR 320 analyze the 'NCoA DAD reply option' of the new handover acknowledgment message to determine whether the set nCoA is an available address, an unusable address, or an unused alternative address. I can figure it out.

The embodiments of the present invention described above are not implemented only by the apparatus and / or method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiments of the present invention, a recording medium on which the program is recorded, and the like. Such implementations may be readily implemented by those skilled in the art from the description of the above-described embodiments.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

1 is a diagram illustrating a conventional mobile IPv6 handover procedure.

2 is a diagram illustrating a conventional procedure for performing FMIPv6 handover.

3 is a diagram schematically showing the configuration of the FMIPv6 handover system according to an embodiment of the present invention.

4 is a block diagram schematically showing the internal configuration of the FMIPv6 handover apparatus according to an embodiment of the present invention.

5 is a diagram illustrating a format of a new handover start message according to an embodiment of the present invention.

6 illustrates a format of a new handover approval message according to an embodiment of the present invention.

7 is a view for explaining a method for performing FMIPv6 handover according to an embodiment of the present invention.

8 is a diagram illustrating a lookup delay time as a result of a simulation of performing an address duplication check according to an exemplary embodiment of the present invention.

Claims (8)

In the high-speed mobile IPv6 handover method by sending and receiving messages between the old access router and the new access router when the mobile station moves to a new network, (a) a new handover initiation message from the previous access router to which the mobile station is connected via a previous access point—the new handover initiation message corresponds to a new Care of Address address redundancy check of the mobile station. Receiving a flag comprising an address duplication check request bit for applying an advanced lookup technique; (b) performing a fast address duplication check by performing a lookup technique applied to a Patricia Trie technique to a neighbor cache when the flag among the reservation flags of the received new handover start message exists; And (c) after performing the fast address duplication check, a new handover grant message in response to the new handover start message, wherein the new handover grant message includes a new Care of Address Address Duplicate Check response option. Generating and transmitting to the previous access router Handover method comprising a. According to claim 1, After step (c), Receiving a fast binding response message including the new care of address address duplication check response option from the old access router and receiving a buffered packet at the old access router Handover method further comprising. In a high speed mobile IPv6 handover system when a mobile terminal moves to a new network, A new handover start message to perform L2 handover with the mobile station and to perform packet tunneling and a new care of address address duplication check of the mobile station-the new handover start message is the new care Includes, and sends, a flag of address duplicate check request bits to apply an advanced lookup technique to of address address duplication check, and sends a new handover acknowledge message in response to the new handover start message. A previous access router receiving; And If the flag is present in the reservation flag of the new handover start message received from the previous access router, a lookup technique applying the Patricia Trie technique is performed to the neighbor cache, and a new care of address address duplication check is performed. A new access router that generates the new handover grant message including a response option and sends it to the old access router Handover system comprising a. The method of claim 3, wherein Receive a router advertisement message including prefix information and address of the new access router from the new access router, extract and store the prefix information from the received router advertisement message, and store the router including the prefix information and its ID. New access point that generates and periodically broadcasts Stored Router Advertisement messages Handover system further comprising. The method according to claim 3 or 4, When the old access router receives the new handover grant message, the old access router generates a fast binding response message including the new care of address address duplication check response option, and transmits it to the mobile station and the new access router. Handover to the new access router. In the high-speed mobile IPv6 handover device by sending and receiving messages between the old access router and the new access router when the mobile station moves to a new network, A new hand for a new Care of Address address duplication check of the mobile terminal from a previous access router to which the mobile terminal is connected via an access point and for establishing a bidirectional tunnel between the old access router and the new access router. A message receiver configured to receive a New Handover Initiation (NHI); When there is a flag including a new care-of-address duplicate address check request bit in the reserved field of the new handover start message, a fast address duplication checker that performs a lookup technique applied to the Patricia Trie method to the NAVER cache. ; And A message transmitter for generating a new handover acknowledgment message including a new care of address address duplication check response option in response to the new handover initiation message and transmitting it to the previous access router. Handover device comprising a. The method of claim 6, The new handover initiation message adds the new care of address address duplication check request bit defined by the D flag of one bit of the reserved flags in the conventional handover initiation message, and the care of the previous mobile terminal in the option field. A handover device comprising adding an address (Previous MN's CoA) and a previous AR's Global Address (Previous AR's Global Address). The method of claim 6, The new handover response message adds an address duplication check response option bit defined by the F flag of two bits of the reserved flags in the conventional handover response message, and adds a new MAC address and a new link in the option field. Handover device, characterized in that it adds a local address, a new Care of Address duplicate address check response option.

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