KR100526408B1 - Method for fast-Handover using fast release message in based wireless LAN - Google Patents

Abstract

The present invention relates to packet forwarding between access routers generated during handover of a user terminal in the Internet Technology Task Force (IETF) draft document "Fast Handover for Mobile IPv6". Alternatively, the present invention relates to a method for efficiently releasing packet tunneling, and the present invention relates to a user terminal after performing a handover to a new access router area in which a terminal is moved in a WLAN-based IPv6 and mobile IPv6 environment. Defines fast-release messages that can quickly release packet forwarding or tunneling between access routers so that packets can be delivered without loss, thereby releasing packet forwarding or tunneling that may exist even after the user terminal performs a handover. Tie to be used or specified for packet forwarding or tunnel use The present invention relates to a fast handover method using a fast release message based on a wireless LAN, which enables efficient use of resources of an access router by rebalancing a computer.

Description

Fast handover method using fast release message in wireless LAN {Method for fast-Handover using fast release message in based wireless LAN}

The present invention relates to packet forwarding between access routers generated during handover of a user terminal in the Internet Technology Task Force (IETF) draft document "Fast Handover for Mobile IPv6". Alternatively, the present invention relates to a method for efficiently releasing packet tunneling. In particular, a packet transmitted to a user terminal after handover to a new access router area where a terminal is moved in a WLAN-based IPv6 and mobile IPv6 environment is carried out. Define Fast-Release messages that can quickly release packet forwarding or tunneling between access routers for lossless delivery, so that user terminals can release and use packet forwarding or tunneling that may exist after handover. Readjust timer specified for packet forwarding or tunnel use As, but relates to a fast handover method using a high speed release messages in a wireless LAN based to efficiently use the resources of the access router.

In general, wireless LAN is a technology that is replaced with a wireless environment that is easy to install and move from a hub to a subscriber end when building a network.

That is, the wireless LAN has an advantage that it is possible to build a network within a relatively quick time compared to the wired LAN because electromagnetic waves are used from the access point equipment to the terminal equipment instead of laying the wire by wire (cable). It also has the advantage of being able to communicate on the go using laptops and PC cards without staying in a fixed desktop environment.

On the other hand, the "Fast Handover for Mobile IPv6" document defined by the Internet Engineering Task Force (IETF) Internet Engineering Task Force (IETF) documents that the mobile agent is moved to the Home Agent of Mobile IPv6 (Mobile Internet Protocol version 6) when the terminal moves to another network. In order to register the information of the terminal, a binding update message defined in a mobile IPv6 document and a fast binding update message defined in a fast handover draft are used.

1 is a diagram illustrating a configuration of a general WLAN network for accessing the Internet using a WLAN.

As shown therein, reference numeral 10 denotes the Internet, reference numeral 20 denotes a router, reference numerals 31, 32, and 33 denote an access router, and reference numeral 40 denotes a user terminal. (MN, Mobile Node).

In this configuration, when the user terminal 40 moves out of the current WLAN access point area (for example, 31) to another access point area (for example, 33), the terminal 40 Determining whether to handover by measuring the power strength of the existing access router 31 and the access router 33 of the new area, and if determined to be handover, Layer 3 for the access router 33 of the new area (Layer3) Obtain information and perform final handover.

2 shows a procedure in which a handover is made in the terminal and the handover is processed in the flowchart defined in the IETF draft "Fast Handover for Mobile IPv6" standard document.

2 only considers the matters of Layer 3 handover.

Here, reference numeral 40 denotes a user terminal (MN), reference numeral 31 denotes an access router currently in service, and reference numeral 33 denotes an access router to be handed over.

First, in step S11, the user terminal 40 transmits a message (RtSoIPr) for informing the handover to the access router 31 that is currently in service, and the current access router 31 that has received it receives the user terminal in step S12. Send a proxy advertisement message (PrRtAdv) to (40).

Thereafter, in step S13, a message HI indicating a handover is transmitted from the current access router 31 to the handover target access router 33. The handover target access router 33 receives the message HI. Sends a response to the current access router 31.

Next, in step S15 the user terminal 40 transmits the registration information (F-BU) of the terminal to the current access router 31, the current access router 31 receives the received in step S16 the user terminal 40 and the response message (F-BACK) to the handover target access router 33.

The current access router 31 transmits the packet transmitted from the user terminal 40 to the handover target access router 33 in step S17 after transmitting the response message (forward packet), and the user terminal in step S18. 40 transmits a message (F-NA) indicating that the handover is completed to the handover target access router 33.

Subsequently, in step S19, the user terminal 40 and the handover target access router 33 transmit and receive packets directly.

That is, FIG. 2 illustrates a general operation of Fast Handover for Mobile IPv6 and a description of the operation is as follows.

When the user terminal moves to the overlapping wireless LAN area, the user terminal compares the beacon signal reception and power strengths of the access points of different networks, and compares the power points of the access points within the new access router area. When the power strength is strong, the RtSoIPr message for performing the handover is transmitted to the current access router currently connected to perform the handover.

Upon receiving the message, the current access router fills the PrRtAdv message (proxy advertisement message) with a new Care of Address (abbreviated as "CoA") for use in a new WLAN network (handover target access router area). The terminal transmits the HI message including the new CoA and the current CoA of the UE to the handover target access router. In addition, packet forwarding or packet tunneling is performed to send a packet having a current CoA of a user terminal as a destination address to a handover target access router.

Meanwhile, the handover target access router receiving the HI message checks whether a new CoA of the user terminal is available and transmits a HACK message to the current access router in response to the request. If Uflag is set in the HI message, If present, it starts buffering packets sent from the current access router.

In this case, in the case of tunneling, a source address of an outer packet is an address of a current access router, and a destination address is an access router to be handed over. In contrast, the source address of the inner packet is the address of the Correspondent Node, and the destination address is the current CoA.

In case of packet forwarding, the destination address of the packet arriving at the current CoA of the user terminal is changed to a new CoA and transmitted to the handover target access router.

Meanwhile, the user terminal receiving the PrRtAdv message transmits the F-BU message to the current access router in response to the message. This message is generally the last message that the user terminal sends in the current access router area before the L2 handover, and the current access router which received this message starts to forward or tunnel the packet.

In addition, the current access router receiving the HACK message transmits the FACK message to the user terminal whether or not to use the HACK message as a new CoA of the user terminal. This message may be sent to the current access router or to a handover target access router.

On the other hand, if the new CoA is not available in the handover target access router occurs, the user terminal uses the current CoA in the handover target access router area and receives the advertisement message and binds with the general mobile IPv6 acquisition of the CoA. Perform the binding process.

If the user terminal does not receive the F-BACK message from the current access router, it performs L2 handover to the area of the handover target access router, and after receiving the message after receiving the access point of the handover target access router, Regardless, it sends an F-NA message to the handover target access router.

In this case, after connecting to the corresponding access point of the handover target access router, an L2 link up trigger occurs at the access point, and the handover target access router receiving this is replaced with an F-NA. Done. At this time, a packet buffered by the handover target access router is transmitted to the user terminal. If there is no link up trigger, this role is substituted by the F-NA message.

Meanwhile, the handover target access router receiving the F-NA message sends an F-NA response message to inform the user terminal of whether a new CoA is available. Perform the binding process. In addition, if it is not available, it receives the advertisement message and performs CoA acquisition and binding process of general mobile IPv6.

That is, as is well known, Mobile IPv6 (Internet IPv6) defined by the Internet Engineering Task Force (IETF) receives a Router Advertisement message transmitted from a home agent of Mobile IPv6 when a user terminal moves to another network. After that, it detects the fact that the user terminal has moved to another network.

In contrast, Fast Handover for Mobile IPv6 checks information on an access point to which a user terminal moves by receiving a beacon signal of an access point when the wireless access network is a wireless LAN. The above information is used to communicate with the access router to pre-configure and allocate CoA for use in the new network. At this time, the user terminal performs a layer 2 handover to the access point after the layer 3 handover in advance, and continues communication using the new CoA. In this case, if a new CoA is not allocated, communication is continued using the current CoA.

However, since the new CoA used in the handover target access router has not processed the Binding Update message of the mobile IPv6, the receiving address of the data sent from the Correspondent node to the user terminal is currently the CoA. Accordingly, a method of transferring data to a user terminal by converting the received address into a new CoA or by forwarding a packet or forming a tunnel between access routers is used.

However, to date, the packet forwarding or tunnel duration is the lifetime set in the high-speed handover message (F-BU message or F-BACK message) (part of execution time, how long any one language object exists). Since it only depends on the value, it is impossible to change this time once set.

Therefore, if the above value is expired while the binding update of the mobile IPv6 is not processed, data is not delivered to the user terminal, which causes a problem of packet loss.

Accordingly, the present invention is proposed to solve the above problems of the prior art,

An object of the present invention is to define a high-speed release message including information on a new network to which a user terminal is moved in a WLAN-based IPv6 and mobile IPv6 environment, and thus, an Internet Technical Task Force (IETF) draft document, " WLAN based to efficiently release packet forwarding or packet tunneling between access routers generated during handover of user terminal in Fast Handover for Mobile IPv6 " To provide a fast handover method using a fast release message in.

The present invention for achieving the above object, in a WLAN-based communication system consisting of a user terminal, a current access router currently in service, a handover target access router, when the user terminal moves to a new network, periodically After comparing the power strength of the current access router and the power strength of the handover target access router to determine whether the handover is large or small, if it is determined that the handover is performed, an address for routing with the handover target access router is generated. In the method for performing a handover using the same, When the user terminal receives a binding response for a new binding from a communication node (Correspondent Node) and a Home Agent (Communication Node) to communicate with, the user terminal from the Current access router or handover target access router Sending a message with the release of high-speed;

When the fast release message is received by the current access router or the handover target access router, retrieving internal information of the message and releasing packet forwarding or tunnel information for the corresponding address. It is done.

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Hereinafter, a preferred embodiment of the "fast handover method using a fast release message based on a wireless LAN" according to the present invention will be described in detail with reference to the accompanying drawings.

3 is a flowchart illustrating a fast handover method using a fast release message in a WLAN based on the present invention.

Here, reference numeral 40 denotes a user terminal (MN), reference numeral 31 denotes an access router currently in service, and reference numeral 33 denotes an access router to be handed over.

As shown in FIG. 3, the user terminal 40 compares the power strength of the current access router 31 with the power strength of the handover target access router 33 to determine whether or not the handover is performed in a large or small size. When it is determined that the handover is determined, generating an address for routing with the handover target access router, and transmitting a message (RtSoIPr) for informing the handover to the currently serving access router 31 (S101); Transmitting a proxy advertisement message (PrRtAdv) from the current access router (31) to the user terminal (40) receiving the message; and from the current access router (31) to the handover target access router (33). Transmitting a message HI indicating a handover (S103), and the handover target access router 33 receiving the message (HI) transmits a response thereto to the current access router 31; (S104), transmitting the registration information (F-BU) of the terminal from the user terminal 40 to the current access router 31 (S105), and the current access router 31 is the user terminal ( 40) and transmitting a response message (F-BACK) to the handover target access router 33 (S106), and after transmitting the response message from the current access router 31, the handover target access router ( 33) transmitting the packet transmitted from the user terminal 40 to the handover (S107), and a message (F-NA) indicating that the handover is completed from the user terminal 40 to the handover target access router 33 (F-NA). In step S108 and, when the handover complete message is transmitted, the user terminal 40 and the handover target access pointer 33 directly transmit and receive a packet in step S109 and the user terminal 40. Correspondent Node with) When a binding response for a new binding is received from a home agent, a fast release message is transmitted from the user terminal 40 to the current access router 31 or the handover target access router 33, and the The current access router 31 or the handover target access router 33 retrieves the internal information of the received message and releases the packet forwarding or tunnel information for the corresponding address (S110) (S111). It is done.

On the other hand, each time the user terminal 40 moves to the handover target access router area and the packet transmitted above arrives to the access router until the binding process of the mobile IPv6 is completed, it resets the initially set lifetime value and delivers the packet. Do this.

Detailed description of the fast handover method using the fast release message in the WLAN based on the present invention as described above is as follows.

First, the time of destruction of the currently generated tunnel and the time of interruption of packet forwarding are not clearly defined in the specification other than the life time option, and the above life time cannot be changed once determined.

Accordingly, the present invention provides a method that does not depend on the lifetime value or a method of changing the lifetime value.

That is, in a manner not dependent on the lifetime value, the lifetime value can be set indefinitely, and a fast release message can be defined to release packet forwarding or tunnel at the access router receiving the message. Alternatively, each time a packet forwarded and tunneled packet arrives at the access router, the lifetime value is reset to enable packet forwarding.

In addition, the method of defining a new message uses the new message as a trigger for packet forwarding or destruction or interruption of the tunnel at the access router. On the other hand, the transmission time of the message in the user terminal is a time when the user terminal receives a binding response (Binding Acknowledge) for the new binding from the communication node (Correspondent Node) and the home agent (Home Agent).

Meanwhile, the configuration of the fast release message generated in the user terminal is as follows.

That is, the source address of the IP header address becomes a new care-of address (CoA), and the destination address becomes the address of the current access router and the handover target access router. At this time, the fast release message is simultaneously sent to the current access router and the handover target access router.

In addition, the quick release message includes the following information.

end. Current referral address of mobile node (Old CoA)

I. New CoA of Mobile Node

All. Home address of the mobile node

Meanwhile, the current access router or handover target access router releases the information of packet forwarding or packet tunneling for the corresponding address by searching for internal information after receiving the message defined above.

Each time a packet arrives at the access router, the life time value is set again so that the packet is delivered.

That is, as shown in FIG. 3, after the user terminal moves to the handover target access router area, the destination address of the packet directed to the user terminal at the current access router is determined by the current CoA until the end of the binding process of the mobile IPv6. do.

On the other hand, when the packet arrives as described above, the lifetime value is initially increased according to a value determined for each service, and the maximum value is set in the fast handover message, the F-BU message, or the F-BACK message. By setting a lifetime value, the infinite increase in the lifetime value is prevented.

Here, in general, since the streaming service has a large amount of traffic and receives a lot of packets, the life time increase value is reduced and other services have a larger value than the streaming service.

Meanwhile, the present invention as described above is limited to the operation until the binding process is completed after the user terminal moves to a new network, and after the binding process is completed, the mobile IPv6 processing procedure is followed.

In other words, the IETF "Fast Handover Mobile IPv6" draft includes a packet forwarding or a tunnel (for packet forwarding) or a packet arriving at the current CoA of the user terminal before the binding update of the mobile IPv6 is processed. Tunnel to the handover target access router.

Until now, it is impossible to change this time once it is set, because the packet forwarding or tunnel duration depends only on the lifetime value of the fast handover message.

Accordingly, in the above case, when the binding update of the mobile IPv6 has not been processed, packet loss may occur because data is not transmitted to the user terminal when the lifetime value expires.

Accordingly, the present invention is to provide a method that does not depend on the lifetime value or a method that can change the lifetime value,

That is, in a manner that does not depend on a lifetime value, the lifetime value is set to infinity, defines a fast release message that can release packet forwarding or tunnel, and defines the fast release message. It is possible to release packet forwarding or tunneling at a received access router or to reset the lifetime value every time a packet forwarded or tunneled packet arrives at the access router so that packet forwarding is performed smoothly.

Meanwhile, in the detailed description of the present invention as described above, a specific embodiment of a fast handover method using a fast release message on a WLAN is described, but the present invention is not limited to the scope of the present invention. There are several variations available. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents of the claims.

According to the above-described "fast handover method using a fast release message based on wireless LAN" according to the present invention, a fast release message including information on a new network to which a user terminal is moved in a WLAN-based IPv6 and mobile IPv6 environment. In this example, the IETF draft document "Fast Handover for Mobile IPv6" enables efficient release of packet forwarding or packet tunneling between access routers generated during handover of a user terminal, thereby efficiently using resources of the access router. Has the advantage.

In addition, the present invention can be applied to a technology for fast handover in an access network using a wireless LAN-based communication system and related technologies that are currently emerging, and a technology for mobility of services including users in a wireless access network in a future mobile communication system. In addition, this technology also has the advantage that can be applied to the access network using a wireless technology other than WLAN.

1 is a diagram showing the configuration of a typical WLAN network for accessing the Internet using a WLAN,

2 is a flowchart illustrating a handover method defined in an IETF draft standard document based on a conventional WLAN;

3 is a flowchart illustrating a fast handover method using a fast release message in a WLAN based on the present invention.

<Explanation of symbols for the main parts of the drawings>

31 ..... Old Access Router

33 ..... New Access Router

40 ..... User Node (MN)

Claims (7)

In a WLAN-based communication system including a user terminal, a current access router currently serving, and a handover target access router, when the user terminal moves to a new network, the power strength of the current access router and the handover target access periodically In the method of comparing the power strength of the router to determine whether the handover to a large or small, and if the handover is determined to generate an address for routing to the handover target access router, and performing the handover using the same, Fast release from the user terminal to the current access router or the handover target access router when the user terminal receives a binding response for a new binding from a communication node and a home agent. Sending a message; When the fast release message is received by the current access router or the handover target access router, retrieving internal information of the message and releasing packet forwarding or tunnel information for the corresponding address. Fast handover method using fast release message on LAN. delete The method of claim 1, wherein the source address of the IP header address included in the fast release message is a new referral address (CoA), and the destination address is a current access router and a handover target access router. A fast handover method using a fast release message in a wireless LAN, characterized in that the transmission to the address of the. The method of claim 1, After the user terminal moves to the handover target access router area, each time a packet whose destination address is the current care-of address (Old CoA) arrives at the access router, the initial lifetime value is set to a value determined for each service. A fast handover method using a fast release message based on a wireless LAN, characterized by increasing accordingly and preventing an infinite increase by setting a maximum value. delete The method of claim 4, wherein the maximum value is, A fast handover method using a fast release message in a WLAN, characterized in that it is set not to be greater than the lifetime value set in the fast handover message (F-BU message or F-BACK message). The method of claim 1, The above-described processing is limited to an operation from when the user terminal moves to the handover target area until the binding processing is completed, and after the binding processing is completed, a mobile IPv6 processing process is performed. Fast Handover Method using Fast Release Message on the Base.