KR20090055916A - The fast vertical handover method for utilizing the network access identifier - Google Patents

Abstract

A fast vertical handover method for utilizing a network access identifier is provided to realize fast handover between heterogeneous networks with a defined network access identifier by newly defining the network access identifier. A router solicit proxy message(RtSoIPr) is transmitted to a PAR(Previous AR)(402), and a proxy router advertisement message(RtAdv) is transferred to an MN(Mobile Node) as response(404). A fast binding update message(FBU) is transmitted to the PAR(406), and a handover initiate message(HI) is transmitted to an NAR(New AR)(408). The validity of NCoA(New Care of Address) is verified and transferred to the PAR(410). A tunnel is generated between a PCoA(Previous Care of Address) and the NCoA(414), and a UNA(Unsolicited Neighbor Advertisement) message is transferred to the NAR(416).

Description

Fast handover method between heterogeneous networks using network access identifier {THE FAST VERTICAL HANDOVER METHOD FOR UTILIZING THE NETWORK ACCESS IDENTIFIER}

The present invention relates to a mobile network, and more particularly, to a method for fast handover between heterogeneous networks using a network access identifier (Network Access Identifier).

The present invention is derived from research conducted as part of the IT growth engine technology development project of the Ministry of Information and Communication and the Ministry of Information and Communication Research. [Task Management Number: 2005-S-404-33, Task name: 3G Evolution terminal technology development].

According to the fast handoff technology, an access router to which a terminal is connected before handover is referred to as a previous access router (hereinafter referred to as a 'PAR'), and a new access router to which the terminal is connected after a handover (New Access Router) is called 'NAR'.

Since the message flow of the fast handoff does not occur sequentially with the handover procedure of the link layer, the message flow can be classified into three types according to the state of the link. First, as shown in FIG. 1, when a handover request is transmitted from the PAR to the NAR in advance and a response is received; It is the case that the over request could not be sent. In the second and third cases, a fast handover is performed at the link layer, so that fast handover message processing does not occur sequentially. The message parameters are the same as those of FIG. 1 to be described.

Hereinafter, a general fast handover message transmission flow in a mobile network will be described with reference to FIG. 1.

First, a mobile node (also referred to as a mobile node (MN)) scans a periphery to be handed over, and searches for an AP ID list and a link layer address (LLA), which is terminal identification information. A Router Solicitation for Proxy (hereinafter referred to as RtSolPr) message is transmitted to the PAR (step 100). Upon receiving this RtSolPr message, the PAR receives information of the corresponding access routers that manage radio access identification information received from the terminal, that is, network prefix information of NAR, IP address of NAR, link layer address of NAR, etc. A proxy router advertisement message including a link layer address (hereinafter referred to as 'PrRtAdv') is delivered to the terminal as a response to the RtSolPr message (step 102).

When the UE receives the PrRtAdv message, it can obtain the subnet IP address information of the neighboring ARs (Access Routers). If it determines that it needs to handover, it can obtain an IP address corresponding to the subnet IP address to be handed over according to the automatic IP address configuration procedure. Acquire. When the network to be handed over is determined, the terminal generates a new care (New Care of Address (NCoA)) to be used after handover using the information of the corresponding NAR. The terminal transmits a fast binding update (hereinafter referred to as 'FBU') message to the PAR including NCDF and tunnel lifetime and a BADF (Binding Authorization Data for FMIPv6) for authenticating that the message is generated by the terminal. (Step 104).

The PAR receiving the FBU message selects a NAR related to the NCoA generated by the terminal and starts handover to the corresponding NAR so that the NAR can perform NCoA address verification and packet buffering (Handover Initiate: hereinafter referred to as 'HI'). Send a message to the NAR (step 106). The HI message 106 includes a terminal identifier LLA, a previous care of address (PCoA) and a new care of address (NCoA). The NAR validates the NCoA included in the HI message, and delivers the result to the PAR through a handover acknowledgment (Hack) message (step 108). Accordingly, the PAR receives the Hack message and delivers the result to the terminal (and to the NAR) through a fast binding acknowledgment (FBAc) message (step 110). At this time, a tunnel between the PCoA and the NCoA is created in the UE and the PAR (step 112).

For reference, when the MN registers the MIP, the tunnel is deleted, and the PAR is kept for several seconds before deleting the tunnel. Packets transmitted to the PCoA are tunneled from the PAR to the NCoA and delivered to the NAR, and the packets transmitted to the NCoA are buffered in the NAR until an Unsolicited Neighbor Advertisement (UNA) message is received from the terminal. As soon as the terminal terminates the establishment of a new link, it must transmit a UNA message to the NAR, and through this, the NAR can confirm that the terminal is connected to itself. In this case, the identifier for identifying the terminal is a link layer address (LLA). If the link layer address (LLA) included in the UNA matches the LLA included in the HI, the buffered packets are forwarded to the terminal.

In the general fast handover technique described above, the PAR includes a link layer address (LLA) of the terminal as a terminal identifier. The PAR receives the link layer address (LLA) of the terminal through the RtSolPr message, and the NAR receives the terminal identifier through the HI message received from the PAR. The terminal identifier received by the NAR is for detecting the connection of the corresponding terminal, and it is possible to confirm that the corresponding terminal is connected by comparing the terminal identifier included in the UNA message with the terminal identifier included in the HI message.

However, the above-described general fast handover technique cannot be applied to handover between heterogeneous networks using different link layers. This is because different link layer separators are used in different networks. Therefore, in order to apply the fast handover technology to the inter-network handover technology, a new management and processing method for terminal identifiers should be newly proposed.

Accordingly, an object of the present invention is to provide a method capable of supporting fast handover even in heterogeneous network handover.

Furthermore, another object of the present invention is to provide a method for newly defining a network access identifier to implement a fast handover between heterogeneous networks, and to implement a heterogeneous fast handover using the defined network access identifier.

The method of the present invention for achieving the above object is a method for a fast handover of a mobile node to a second access router of a heterogeneous network through a first access router,

Inserting network access identifier (NAI) information into a message requiring terminal identifier information insertion among messages defined to be exchanged with the access routers to implement fast handover;

And selectively transmitting the message with different attributes inserted with the network access identifier (NAI) information to any one of the access routers in a defined order.

Furthermore, another method of the present invention for achieving the above object,

Transmitting a router request proxy message including a discovered radio access identification list and a network access identifier (NAI) which is a terminal identifier to the first access router;

Receiving a proxy router advertisement message from the first access router;

Sending a fast binding update message including the network access identifier (NAI) to the first access router;

Receiving a fast binding response message from the first access router;

Establishing a new link with reference to the information included in the received message, and transmitting a UNA (Unsolicited Neighbor Advertisement) message including network access identifier (NAI) information to the second access router for fast handover; It is characterized by including.

Furthermore, the system of the present invention for achieving the above object,

A mobile node (MN) that transmits a network request identifier (NAI) as terminal identifier information in each of a router request proxy message (RtSolPr) and a fast binding update message (FBU) among messages defined to be exchanged for fast handover. Wow;

Receive a fast binding update message (FBU) from the mobile node (MN), and selects an access router associated with the new address information (NCoA) of the mobile node included in the message and transmits a handover initiation message (HI), A first access router (PAR) transmitting the network access identifier (NAI) information in a message HI;

When an Unsolicited Neighbor Advertisement message is received from the mobile node MN, the network access identifier NAI included in the message is included in the handover initiation message HI. And a second access router (NAR) for authenticating the mobile node in comparison with the information.

According to the problem solving means of the above-described configuration, in order to implement high-speed handover between heterogeneous networks, the terminal can receive network access identifier (Network Access Identifier) information that can be identically distinguished in all networks without using a general link layer address (LLA). Since the present invention is used as an identifier, the present invention can support fast handover even in heterogeneous network handover.

In addition, by enabling high-speed handover between heterogeneous networks, a side effect of reducing packet loss due to handover delay can be obtained.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

First, FIG. 2 illustrates a configuration diagram of a heterogeneous high speed handover system to which the present invention is applied.

As shown in FIG. 2, there are three main types of networks to which a user terminal corresponding to a mobile node can access, for example, a 3GPP access network 201, a 3GPP access-based WLAN access network 202, and a WLAN. There is a network 203. In the 3GPP access network 201, the mobile node 204 may use the 3GPP service by accessing an E-NodeB 205 that is in charge of wireless access and an Access Gateway (AGW) 206 that is in charge of a router. . In the 3GPP connection-based wireless LAN network 202, the mobile node terminal 204 performs a wireless connection using the wireless access point 207, and accesses through a packet data gateway (PDG) 208 which is a 3GPP access router. 3GPP services are available. In the WLAN network 203, the mobile node terminal 204 may establish a wireless connection using the wireless access point 209 and use an Internet service through an access router (AR) 110. The AGWs 206, PDGs 208, and routers 210 of each access network play the role of an access router (AR) defined in a fast handoff technique.

More specifically, in the exemplary system, the mobile node terminal 204 is a router request proxy message (RtSolPr), a fast binding update message (FBU), and unsolicited neighbor advertisement (Unsolicited) among the messages defined to be exchanged for fast handover. Neighbor Advertisement (UNA) message includes Network Access Identifier (NAI) information as terminal identifier information and is transmitted.

The 'NAI' information is terminal identifier information used to identify a terminal during handover between heterogeneous networks, and can be identified in all networks. In order to use the network access identifier as the terminal identifier information, first, as shown in (b) of FIG. 3, new code information for indicating handover between heterogeneous networks is indicated in an option code field of a fast handover related message. Must be assigned.

For reference, the option format defined for the LLA in the current fast handover message is shown in FIG. According to the message definition, the type value is 1 byte long, the value is defined as 19, and the Length field is defined as 1 byte. 8 bytes containing the type, length, and option code of the LLA option are denoted by 1. In the option code field, codes for each application are defined, which are currently defined from 1 to 7. Therefore, for the implementation of the present invention, any one after 8 is newly defined as terminal identifier information for fast handover between heterogeneous networks, and as shown in (b) of FIG. 3, the actual network access identifier which is terminal identifier information after the option code field as shown in FIG. The allocation of the (NAI) information allows the link layer to recognize the terminal identifier in the same way when handover between different networks.

Referring back to FIG. 2, if the access routers 206, 208, and 210 serving as routers in each access network are access routers (PARs) connecting with the mobile node 204 prior to handover, the access routers may be described. Receive a fast binding update message (FBU) from the mobile node 204, select an access router associated with the new address information (NCoA) of the mobile node included in the message, and transmit a handover initiation message (HI). (HI) is responsible for transmitting the network access identifier (NAI) information including.

On the other hand, if the access routers 206, 208, and 210 serving as routers in each access network are access routers (NARs) connecting with the mobile node 204 after the handover, the access router requests from the mobile node 204. When an Unsolicited Neighbor Advertisement message is received, mobile node authentication is performed by comparing the network access identifier (NAI) information included in the message with the network access identifier (NAI) information included in the handover initiation message (HI). It plays a role. That is, each of the access routers illustrated in the system may be a PAR or NAR as necessary.

Hereinafter, a process of implementing a fast handover between heterogeneous networks between the mobile node 204 and each access router in response to the message defined for the fast handover will be described in detail with reference to FIG. 4.

Prior to the description of the embodiment, since the message flow of the fast handover does not occur sequentially with the handover procedure of the link layer, the message flow may be classified into three types according to the link state. The first is a case of handing a handover request from the PAR to the NAR in advance and receiving a response. The second is a case of making a handover request through the NAR again because the handover request was made in advance but the response was not received. Finally, the handover request cannot be transmitted. In all these cases, the message parameter definitions are all the same, and therefore, the embodiment of the present invention will be described assuming the first case.

Referring to FIG. 4, first, a mobile node 204 of a 3GPP access network scans a periphery to be handed over, and then searches for an AP ID list and a network access identifier (NAI) which is terminal identification information. Is included in the router request proxy message RtSolPr and transmitted to the currently connected PAR 206 (step 402). Upon receiving the Router Solicitation Proxy message (RtSolPr), the PAR 206 is responsible for managing the radio access identifiers received from the mobile node 204, namely the network prefix information of the NAR, the IP address of the NAR, the link layer of the NAR. The proxy router advertisement message RtAdv including information such as an address is forwarded to the mobile node 204 in response to the router request proxy message RtSolPr (step 404).

The mobile node 204 receiving the proxy router advertisement message PrRtAdv then generates a new address NCoA to be used after handover using the information of the corresponding NAR when the network to be handed over is determined. The mobile node 204 also sends a fast binding update message (FBU) including a NCoA, tunnel lifetime, network access identifier (NAI) information, which is a terminal identifier, and a BADF that can authenticate the message generated by the terminal. To the side (step 406).

After receiving the fast binding update message (FBU), the PAR 206 selects a NAR related to the NCoA generated by the mobile node 204 (for example, the access router 210 of the WLAN access network), and selects the corresponding NAR ( In step 408, the handover start message HI is transmitted to the NAR 210 so that the 210 performs NCoA address verification and packet buffering. The handover initiation message HI includes a terminal identifier NAI, a PCoA and a NCoA, which are the previous addresses of the terminal.

Meanwhile, the NAR 210, which is the access router of the WLAN access network, validates the NCoA included in the HI message and transmits the result to the PAR 206, which is the access router of the 3GPP access network, via a handover response message (HAck) (410). Step). Upon receiving the handover response message (Hack), the PAR 206 transmits the result to the mobile node terminal 204 through the fast binding response message FBAck (step 412). At this time, a tunnel between the PCoA and the NCoA is generated in the mobile terminal 204 and the PAR 206 (step 414). The generated tunnel is deleted upon MIP registration on the mobile node 204 side, and maintained for several seconds on the PAR 206 side. For reference, packets transmitted to PCoA are tunneled to NCoA at PAR 206 and delivered to NAR 210. Packets sent to NCoA are transmitted at NAR 206 until UNA messages are transmitted from mobile node 204. Buffered.

Meanwhile, the mobile node 204 establishes a new link with reference to the information included in the received messages PrRtAdv and FBAck, and then transmits a UNA message to the NAR 210 (step 416). Accordingly, the NAR 210 may confirm that the mobile node 204 is connected to itself through the UNA message. At this time, the identifier for authenticating the terminal is a link layer address (LLA). Therefore, the NAR 210 forwards the buffered packets to the mobile station 204 when the link layer address included in the UNA message matches the network access identifier (NAI) included in the handover initiation message HI.

Therefore, the mobile node 204 obtains the result of the fast handover from the 3GPP access network to the WLAN access network.

As in the above embodiment, since the present invention uses network access identifier (NAI) information that is equally distinguishable in all networks without using a general link layer address (LLA) to implement high-speed handover between heterogeneous networks, High speed handover can be implemented even in heterogeneous network handover.

1 is a flow diagram of a typical fast handover message transmission.

2 is an exemplary configuration of a high speed handover system between heterogeneous networks to which the present invention is applied.

3 is an exemplary message format related to handover according to an embodiment of the present invention.

4 is a flowchart of a fast handover message transmission according to an embodiment of the present invention.

Claims (5)

A method for a fast handover of a mobile node to a second access router of a heterogeneous network through a first access router, the method comprising: Inserting network access identifier information into a message requiring terminal identifier information insertion among messages defined to be exchanged with the access routers to implement fast handover; And selectively transmitting the message of the different attributes inserted with the network access identifier information to any one of the access routers in a defined order. 2. The method of claim 1, wherein code information indicating a handover between heterogeneous networks is inserted in each option code field of messages including the network access identifier, and the network access identifier information is inserted after the option code field interval. Fast handover method between heterogeneous networks. The method of claim 1 or 2, wherein the message including the network access identifier information is a router request proxy message, a fast binding update message, or an unsolicited neighbor advertisement message. A method for a fast handover of a mobile node to a second access router of a heterogeneous network through a first access router, the method comprising: Transmitting a router request proxy message including a searched radio access identification list and a network access identifier which is a terminal identifier to the first access router; Receiving a proxy router advertisement message from the first access router; Sending a fast binding update message including the network access identifier to the first access router; Receiving a fast binding response message from the first access router; And establishing a new link with reference to the information included in the received message, and transmitting a unsolicited neighbor advertisement message including network access identifier information to the second access router for fast handover. High speed handover method between heterogeneous networks. The method of claim 4, wherein the option code fields of the messages including the network access identifier include code information indicating handover between heterogeneous networks, and the network access identifier information is included after the option code field section. Fast handover method between heterogeneous networks.

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