KR100700526B1 - Method for handover on mobility network - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a handover method in a wireless network, and more particularly, to apply overhead and packet fragmentation by applying an address translation method rather than a tunneling method in a hierarchical handover in a micro mobility environment. The purpose of this is to remove and enable smooth packet transmission and reception. The present invention for this purpose, a mobile node for providing a mobile service, a counterpart node communicating with the mobile node, a plurality of routers linked to and communicate with the mobile node, and a mobility anchor point for relaying communication between the plurality of routers. A packet transmission method in a network including a Mobility Anchor Point (hereinafter abbreviated as " MAP "), the method comprising: obtaining a care-of address (CoA) from a router where the mobile node is currently located; Registering, by the mobile node, the obtained care-of address with the counterpart node and the MAP; Checking, by the MAP, whether there is a transport packet from the counterpart node to the mobile node; When the MAP identifies a transport packet from the counterpart node to the mobile node, the MAP intercepts the packet and converts the destination address in the packet into a registered address of the registered mobile node; And the router linked to the mobile node performs routing of the packet whose destination address has been translated to the mobile node.

Description

Handover method in wireless network {METHOD FOR HANDOVER ON MOBILITY NETWORK}

1 is a topology of an HMIPv6-based network.

2 is a signal flow diagram illustrating a conventional handover process.

3 is a signal flow diagram illustrating a tunneling scheme in FIG.

4 is a signal flow diagram illustrating a message processing flow in an embodiment of the present invention.

5 is a signal flow diagram illustrating an address conversion process in an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

410: mobile node (MN) 421, 422: access router (AR)

430: MAP (Mobility Anchor Point) 440: Relative Node (CN)

The present invention relates to mobile services, and more particularly, to a handover method in a wireless network.

Recently, with the spread of mobile terminals and the realization of high speed networks, the demand for Internet services is increasing. That is, the number of users has increased greatly due to the improvement of the performance of mobile terminals such as portable computers and PDAs and the development of wireless communication technologies.

An IP address, an Internet address system, consists of a network identifier field and a host identifier field. The network identifier field is a part for identifying a network, and the host identifier field is a part for identifying a host in one network.

When the mobile terminal moves to another network, the network identifier is changed and therefore the IP address of the mobile terminal is also changed. This means that packets in the IP layer are routed according to the network identifier of the destination address, so that the mobile terminal cannot communicate when moved to another network.

If you want to continue to communicate in another network that has moved, you need to change the IP address to have the network identifier of the network every time you move the network.

However, if the IP address is changed to have the network identifier of the corresponding network, higher layer connection is not guaranteed.

Therefore, in order to keep communication while maintaining an existing IP address, mobility must be guaranteed.

Mobile IP (hereinafter referred to as 'MIP') has been proposed to ensure mobility in the Internet environment.

However, the recent trend of increasing the number of wireless Internet users is that MIPv4's addressing system is 32-bit, which cannot meet the ever-increasing IP address requirements. There is an active research to provide mobility.

MIPv6 has the advantage of transparency because the application needs to be installed only on three related nodes, namely, a Correspondent Node (CN), a Home Agent (HA), and a Mobile Node (MN).

In addition, MIPv6 can use the existing IP procedure for link disconnection detection and registration to a new subnet.

The basic operation of the MIPv6 will be described as follows.

When the mobile node MN moves from the home network to the external network, the mobile node MN obtains a care-of-address (hereinafter referred to as 'CoA') from an agent of the currently located subnet. That is, when the mobile node MN moves from the current subnet to another subnet, the mobile node MN obtains a new CoA from the new subnet.

The mobile node MN binds a home address and the new CoA and registers it with a partner node CN to which the home agent HA of the home network communicates with the mobile node MN itself.

Accordingly, the counterpart node CN sets the destination of the packet to be transmitted to the mobile node MN as the new CoA and transmits the packet, and the home agent HA uses the original home address as the destination. Intercepting the packet transmitted to the mobile node (MN) and tunneling (tunneling) to the mobile node (MN).

However, in MIPv6, there is a problem that packets may be lost while moving due to an increase in demand for real-time traffic. This is represented by the so-called disconnection phenomenon.

As a solution to this problem, the concept of Localized Mobility Management (hereinafter referred to as 'LMM') has been proposed.

In the LMM, even if a mobile node (MN) moves to a new subnet, packets may be routed to the mobile node (MN) without affecting binding data registered in a home agent (HA) or a partner node (CN). This is how you do it. That is, the IP address of the mobile node MN, which is visible to the home agent HA or the counter node CN of the mobile node MN, is not changed.

Hierarchical MIPv6 (hereinafter, abbreviated as 'HMIPv6') has been proposed as a technology that satisfies the LMM condition.

In HMIPv6, a new node called Mobile Anchor Point (abbreviated as 'MAP') has been defined to support hierarchical mobility. The MAP serves as a local mobile agent as a router located in a domain visited by a mobile node MN, and may be located at any layer of routers of a hierarchical structure.

1 shows the basic topology of HMIPv6.

In FIG. 1, the MAP 130 intercepts all packets transmitted to the mobile node 110 registered to the mobile station 110, and abbreviates the current care-of address of the mobile node 110, that is, on-line CoA (hereinafter, referred to as "LCoA"). Tunneling).

When the mobile node 110 moves to a new MAP domain, the mobile node 110 binds its home address with a Regional CoA (hereinafter, abbreviated as "RCoA"), which is a local care address obtained from the new MAP, to form a counterpart node 140. Or register with the home agent 150.

In FIG. 1, reference numerals '121' and '122' are access routers (ARs) connected to the mobile node 110 to perform communication.

HMIPv6 performs two operations, Basic Mode and Extended Mode.

First, in the basic mode, the mobile node 110 adds the subnet prefix of the MAP 130 and the interface ID of the mobile node 110 itself to obtain CoA in a stateless address auto configuration method. This is a globally routable address from the perspective of the partner node 140 or the home agent 150 and is actually an address reachable up to the MAP 130.

The stateless address auto configuration method is a method in which a mobile node (MN) generates an IP address for itself to use, and generates an IP address using a unique identifier (for example, a MAC address) that does not overlap between mobile nodes.

In the extended mode, the mobile node 110 receives the CoA assigned to one of the interfaces of the MAP 130 through the MAP option and uses the same.

Hereinafter, the message flow in HMIPv6 will be described with reference to FIG. 2.

First, the mobile node 110 sends a Binding Update (hereinafter abbreviated as "BU") message to the MAP 130 in order to correctly deliver the packet each time it moves. The BU message is distinguished from a Home Registration or Route Optimization message by setting an M flag in a BU message of MIPv6.

The address to which the mobile node 110 binds is its LCoA.

In addition, the mobile node 110 needs to discover nearby MAPs. One method for this is a method in which the MAP 130 sends a Router Advertisement (RA) message and the mobile node 110 receives and processes the RA message. At this time, the propagation range of the RA message is to an access router (AR) 121 or 122 having an air interface to the mobile node 110.

If the mobile node 110 moves to a new MAP, the mobile node 110 acquires a new RCoA, and then registers a BU message with the counterpart node 140 and the home agent 150.

At this time, the available extension fields include a Preference option that can give a choice according to the load of the MAP 130 and a hop to the MAP to reduce the update between the MAPs when the node is moving rapidly or communicating with the local CN. There is a field that specifies the number of hops.

Therefore, when the other node 140 transmits the packet by setting the destination of the packet transmitted to the mobile node 110 as RCoA, the MAP 130 intercepts the packet to check the address of the packet and access the packet. A new access router (nAR) 122 transmits the data to the mobile node 110.

In conclusion, in HMIPv6, it is possible to reduce delays in binding update by enabling local binding according to topology with nodes acting as MAP to support hierarchical mobility.

Meanwhile, the packet forwarded by the mobile node 110 to the counterpart node 140 or the packet forwarded from the counterpart node 140 to the mobile node 110 may be in the region of the MAP 130 or the home agent 150. In a handover or at handover, both nodes are tunneled and transmitted. Through this, the mobile node 110 may hide its presence from the other node 140 or the existing routing environment. This approach is used in multicast or most mobility methods.

3 illustrates tunneling from MAP 130 to access router 122. This is the tunneling scheme commonly implemented in HMIPv6. The tunneled data is packet encapsulated. Encapsulation is the transmission of IPv6 or IPv4 packets by including them in the data area of IPv4 or IPv6 packets.

However, the conventional HMIPv6 technology has the same delay as the existing MIPv6 in the inter-domain handover, and furthermore, there is a problem in that the transparency of the MIPv6 is reduced by that much.

In addition, packet encapsulation processing of tunneled data not only incurs unintentional overhead in real-time traffic, but also hides packet quality of service (QoS) information in the original packet header and at the same time generates packet fragmentation. There is a problem that can be.

That is, in the conventional handover, the tunneling method is used for packet transmission during handover, and the overhead of packet encapsulation and decapsulation occurs at both nodes of the tunnel, and the QoS in the original packet is hidden. As a result, packet fragmentation may occur as the size of a packet increases.

Accordingly, the present invention provides a smoother by eliminating overhead and packet fragmentation by applying address translation instead of tunneling when hierarchical handover in a micro-mobility environment. It is an object of the present invention to provide a handover method in a wireless network in which packet transmission and reception are performed.

That is, the present invention is to achieve the object of preserving the packet that the mobile node (MN: Mobile Node) by replacing the tunneling scheme with the address translation scheme while maintaining the existing hierarchical handover procedure.

The present invention provides a mobile node for providing a mobile service, a counterpart node communicating with the mobile node, a plurality of routers linked to and communicating with the mobile node, and communication between the plurality of routers. A packet transmission method in a network including a mobility anchor point (abbreviated as "MAP"), the method comprising: obtaining a care-of address (CoA) from a router in which the mobile node is currently located; Registering, by the mobile node, the obtained care-of address with the counterpart node and the MAP; Checking, by the MAP, whether there is a transport packet from the counterpart node to the mobile node; When the MAP identifies a transport packet from the counterpart node to the mobile node, the MAP intercepts the packet and converts the destination address in the packet into a registered address of the registered mobile node; The router linked to the mobile node is configured to perform routing of the packet whose destination address has been translated to the mobile node.

The new CoA is generated by adding the subnet prefix of the MAP and the interface ID of the mobile node itself.

Hereinafter, the present invention will be described in detail with reference to the drawings.

In describing the preferred embodiments of the present invention in detail with reference to the accompanying drawings, in the following description and drawings, numerous specific details such as processing flows are described in order to provide a more comprehensive understanding of the invention, and the gist of the invention. Detailed description of well-known functions and configurations that may unnecessarily obscure will be omitted.

In an embodiment of the present invention, a method for removing tunneling based on the HMIPv6 protocol will be described.

The present invention applies the HMIPv6 scheme at the time of initial registration, and applies the Fast Handovers for Mobile IPv6 (hereinafter abbreviated as "FMIPv6") scheme to signaling of handover. This is to detect the movement of the terminal before connecting to the new router, and to obtain the address of the new subnet in advance through the router advertisement, thereby realizing a substantial delay reduction effect.

That is, the present invention describes a process for achieving reliable handover by having an access router buffering an area where a mobile node (MN) exists for a packet that may be lost during handover. same.

First, when the mobile node 410 receives an advertisement message broadcast from the home agent (HA), the mobile node 410 requests registration from the home agent (HA).

If the advertisement message is not received from the home agent (HA), the mobile node 410 transmits an advertisement solicitation message to the home agent (HA) to request registration. The registration process is based on HMIPv6.

Therefore, the packet transmitted from the counterpart node 440 to the mobile node 410 is intercepted by the home agent HA and delivered to the mobile node 410.

Subsequently, when the mobile node 410 moves out of the area of the home agent HA to an arbitrary area, the mobile node 410 obtains an address of the corresponding mobile area and registers it with the MAP 430.

That is, if the mobile node 410 moves into the area of the access router 422, the mobile node 410 obtains the address LCoA of the access router 422 and registers it with the counterpart node 440 and the MAP 430.

Signaling of the handover is made in the FMIPv6 scheme, which will be described below with reference to FIG. 4.

The mobile node 410 transmits a Router Solicitation Proxy (RtSolPr) message to the MAP 430, and the MAP 430 transmits a Proxy Router Advertisement (PrRtAdv) message to the mobile node 410.

Accordingly, the mobile node 410 transmits a fast binding update (FBU) message to the MAP 430. The FBU message includes the care-of address LCoA obtained by the mobile node 410 from the access router 422.

When the mobile node 410 moves to the area of the access router 422, the MAP 430 transmits a HI (Handover Initiate) message to the access router 422, and the access router 422 A HACK (Handover Acknowledgement) message is transmitted to the MAP 430 for the HI message. At this time, the MAP 430 executes a new binding data registration operation.

Accordingly, the mobile node 410 executes a fast binding acknowledgment (FBAck) operation as it moves from the area of the old access router 421 to the area of the new access router 422.

The MAP 430 transmits a packet defined in the mobile node 410 to the access router 422, and receives the fast neighbor advertisement (FNA) message from the mobile node 410. Forwards the packet to the mobile node 410.

When the other node 440 transmits a packet to the mobile node 410 whose router area is changed, the other node 440 transmits the packet by setting the source to CN and the destination address to RCoA.

In this case, the packet transmitted from the counterpart node 440 is intercepted by the MAP 430 to confirm a destination address, and then changed to a destination address RCoA to LCoA. That is, the MAP 430 transmits the packet transmitted by the counter node 440 to the mobile node 410 to the mobile node 410 with reference to local binding information. The address RCoA set by) is changed to the requested address LCoA of the mobile node 410 and transmitted.

Accordingly, the access router 422 receives the corresponding packet whose destination address is changed in the MAP 430 and transmits the packet to the mobile node 410.

That is, in the present invention, the MAP 430 changes the destination address to the address LCoA of the mobile node 410 for the packet transmitted from the counter node 440, and thus the mobile node 410 at the counter node 440. FIG. By routing the corresponding packet up to), signaling during handover follows the FMIPv6 scheme.

In addition, when the mobile node 410 transmits a packet to a higher layer, the mobile node 410 sets the destination address to RCoA and transmits the packet.

Meanwhile, although preferred embodiments of the present invention have been described above, those skilled in the art will variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. Can be.

As described in detail above, the present invention uses the address translation method without using tunneling between access routers (ARs) for packets transmitted to mobile nodes (MNs) in an inter-domain or inter-domain handover in HMIPv6. Because of the transmission, problems that may occur in the existing tunneling method can be solved.

Accordingly, the present invention has the effect of ensuring reliable packet transmission by allowing the access router in the area where the mobile node MN exists to buffer a packet that may be lost during handover.

Claims (4)

A mobile node providing a mobile service, a counterpart node communicating with the mobile node, a plurality of routers linked and communicating with the mobile node, and a mobility anchor point relaying communication between the plurality of routers. In the packet transmission method in the network (abbreviated as "MAP"), Obtaining a care-of address from the router where the mobile node is currently located; Registering, by the mobile node, the obtained care-of address with the counterpart node and the MAP; Checking, by the MAP, whether there is a transport packet from the counterpart node to the mobile node; When the MAP identifies a transport packet from the counterpart node to the mobile node, the MAP intercepts the packet and converts the destination address in the packet into a registered address of the registered mobile node; And the router linked to the mobile node performs routing of the packet whose destination address is translated to the mobile node. The method of claim 1, wherein the care address is And generating a subnet prefix of the MAP and an interface ID of the mobile node. The method of claim 1, wherein registering the care of address is Handover method in a wireless network, characterized in that the HMIPv6 based. The method of claim 1, wherein the packet transmission Handover method in a wireless network, characterized in that based on FMIPv6.

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