KR20090062272A - Fast handover method using sip based on media independent handover - Google Patents

Abstract

A fast handover method using the MIH-based SIP is provided to perform the inspection for IP redundancy within candidate mobile networks to which a mobile terminal is handed over before setting up an IP address. A mobile terminal generates the first IP address corresponding to each neighboring candidate mobile network(40,42) and then transmits the generated result to each candidate mobile network. The mobile terminal inspects IP redundancy in each candidate mobile network, determines one of the candidate mobile networks as the first candidate mobile network, and then sets up the first IP address as a setup IP address after performing the handover of an L2 layer to the first candidate mobile network, in order to perform the SIP handover.

Description

Fast handover method using SIP based on Media Independent Handover}

The present invention relates to handover of different IP addresses to a network. In particular, the present invention relates to a MIH-based fast handover method in which a mobile terminal performs fast handover using a media independent handover (MIH) and a session initiation protocol (SIP) for a real-time multimedia session.

Currently, the handover method using SIP attempts to connect to a new network when the mobile station is completely disconnected from the network currently being serviced, generates a new IP (Internet Protocol) address, and performs a handover procedure with the generated address. have.

However, the handover process using SIP takes a lot of time, and thus the mobile terminal is not suitable for using a real-time multimedia service. In particular, during the handover process using SIP, a lot of time is required in the process of generating an address and checking address duplication (Duplicated Address Detection).

Therefore, high speed handover is required for real-time multimedia service, and for this purpose, DAD check must be able to be performed quickly.

An object of the present invention is to provide a fast handover method using MIH based SIP that performs fast address generation and fast DAD check for fast handover using SIP.

According to an aspect of the present invention for achieving the above technical problem, a mobile terminal using SIP and MIH provides a method for fast handover to different IP networks. The fast handover method includes: a first step of generating a first IP address corresponding to each candidate mobile network in the vicinity when the mobile station detects a handover occurrence event; Transmitting a first IP address of the corresponding candidate mobile network generated to each candidate mobile network; Performing a redundancy check on the first IP address in each candidate mobile network and informing the mobile station of the redundancy check result; A fourth step of the mobile terminal reflecting the result of the redundancy check and determining a first candidate mobile network to hand over one candidate mobile network among the candidate mobile networks; Performing a handover of an L2 layer to the first candidate mobile network; And performing a handover of the L2 layer and performing a SIP handover using the first IP address for the first candidate mobile network as a set IP address.

In the third step, if the result of the redundancy check fails or the address automatic setting method is changed, the mobile terminal includes the changed address automatic setting method in the response message to the first message and informs the mobile terminal. The present invention may further include a seventh step of generating, by the mobile terminal, a new second IP address according to the changed automatic address setting method.

According to another aspect for achieving the above technical problem, the present invention provides a method for fast handover of a mobile terminal using SIP and MIH to different IP networks. The fast handover method includes a serving PoA (Point of Access) predicting a handover situation of the mobile terminal; Generating, by the serving PoA, a first IP address corresponding to each candidate mobile network in which the mobile station is located; Transmitting, by the serving PoA, the first IP address of the corresponding candidate mobile network generated to each candidate mobile network; Performing a redundancy check on the first IP address in each candidate mobile network and informing the serving PoA of the redundancy check result; A fourth step of the serving PoA reflecting the result of the redundancy check and determining a first candidate mobile network to handover one candidate mobile network among the candidate mobile networks; A fifth step of informing the mobile station of the determined first candidate mobile network, whereby the mobile station performs handover of an L2 layer; And a sixth step of performing SIP handover using the first IP address for the first candidate mobile network, which has been handed over by the L2 layer, as the set IP address.

In the third step, if the result of the redundancy check fails or the address automatic setting method is changed, the mobile terminal is notified to the mobile terminal by including the changed address automatic setting method in the response message to the first message. The present invention may further include a seventh step of the serving PoA generating a new second IP address according to the changed address automatic setting method.

According to an embodiment of the present invention, the present invention can shorten the handover time of the L3 layer performed after the L2 layer handover by performing an IP redundancy check for candidate mobile networks to be handed over before setting an IP address. .

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”, etc. described in the specification mean a unit that processes at least one function or operation, which may be implemented by hardware or software or a combination of hardware and software. have.

In the present specification, a mobile terminal (MT) may include a terminal, a subscriber station (SS), a portable subscriber station (PSS), a user equipment (UE), and an access terminal. Terminal, AT) and the like, and may include all or part of the functions of a mobile terminal, a subscriber station, a portable subscriber station, a user device, and the like.

Now, a fast handover method using MIH based SIP according to an embodiment of the present invention will be described with reference to FIGS. 1 to 7.

1 is a diagram showing a network environment to which the present invention is applied. As shown in FIG. 1, in a network to which the present invention is applied, a first subnet N1 and a second subnet N2 using different IP addresses are mixed, and the mobile terminal 10 is formed of a first subnet. SIP server 30 is established to connect multimedia session with CN (Correspondent Node) 20 using SIP in the first and second subnets (N1, N2), when mobile terminal 10 moves to another subnet. Is a network that supports handover based on MIH.

The mobile terminal 10 is equipped with SIP for communication with the CN 20 through the SIP server 30, has a MIH function capable of MIH-based handover, hereinafter referred to as "SIP terminal" .

The SIP terminal 10 may be configured in a single mode supporting only one interface type when manufactured only for homogeneous network handovers, and may be configured in a multi mode supporting two or more interface types when manufactured for homogeneous network and heterogeneous network handovers. Can be configured. The interface type may be a wire-line interface type such as Ethernet based on IEEE802.3, a wireless interface type based on IEEE802.XX such as IEEE802.11, IEEE802.15, IEEE802.16, or 3GPP. , May be any one of interface types defined by a cellular standardization organization such as 3GPP2. However, the interface type of the present invention is not limited to the above-described type.

The protocol configuration of the SIP terminal 10 is a medium access control layer (MAC; Layer 2) is located on a single-mode or multi-mode physical layer (PHY; Layer 1), the MIH layer is located thereon, the IP layer above the MIH layer (Layer 3) is located. In addition, the upper layer is located above the IP layer, including the SIP layer (session layer) that is responsible for session connection.

The first and second subnets N1 and N2 may be subnets of the same network and may be heterogeneous networks (eg, WCDMA, WLAN, WiBro, HSDPA, etc.).

When the first and second subnets N1 and N2 are the same network, the handover between the first and second subnets N1 and N2 becomes a handover between all homogeneous networks, and the first and second subnets N1 and N2. Is different types of networks, the handover between the first and second subnets becomes a handover between heterogeneous networks.

The first and second subnets N1 and N2 may include at least one point of access (PoA) connecting the SIP terminal 10 to the subnet to which it belongs (eg, an access router, a fore agent, and an AP). Access Point, etc.) is located. Among these PoAs, the PoA applied to the present invention has a MIH function for the user and performs a PoS function for supporting handover based on the MIH of the SIP terminal 10.

Hereinafter, since a handover from the first subnet N1 to the second subnet N2 will be described as an example, the PoA of the first subnet N2 is referred to as a “serving PoA 41”. The PoA of the 2 subnet N2 is called "candidate PoA 42". Here, the candidate PoA 42 may exist as many kinds of mixed networks.

The MIH function facilitates the handover process using input values from the second layer (media access control layer) such as trigger events and information about other networks. In addition, the MIH feature can include user policy and configuration-based inputs that can affect the handover process and include Layer 3 entities such as Mobile IP (MIP). ) And the common interfaces between the MIH functions.

These interfaces provide information about layer 1 (physical layer) and layer 2 (media access control layer) and mobility management. The MIH layer obtains information about lower layers and networks with the help of events and information services. In the upper layer, a higher management entity for monitoring and controlling the status of various links in the mobile terminal is located to perform a handover control function and a device manager function. In this case, the handover control function and the device manager may be independently located, or both functions may be included together as a higher management entity.

Hereinafter, a fast handover method using MIH based SIP according to the first embodiment of the present invention will be described with reference to FIG. 2. 2 is a data flow diagram illustrating a fast handover method using a MIH-based SIP according to the first embodiment of the present invention, when the SIP terminal 10 performs a fast handover using a MIH-based SIP. It is about. Hereinafter, a handover SIP terminal is referred to as a first SIP terminal 10, and a CN 20 communicating with the first SIP terminal 10 through a session is referred to as a second SIP terminal 20.

As illustrated in FIG. 2, the first SIP terminal 10 detects a Link_Going_Down event through the MIH function during communication with the second SIP terminal 20 (S201).

Then, the first SIP terminal 10 transmits MIH_Get_Information Request to IS (Information Server) 40 to obtain characteristic information of neighboring candidate mobile networks according to its location (S202), and from IS server 40. The MIH_Get_Information Response is received (S203).

Here, the MIH_Get_Information Response includes the characteristic information of the candidate mobile network, wherein the characteristic information of the candidate mobile network includes the type (identification information) of each candidate mobile network, IP prefix, address autoconfiguration method, and candidate mobile network. It contains PoA IP address.

Link_Going_Down occurs when a Layer 2 connection is predicted to be Link_Down within a certain time, and Link_Down occurs when a Layer 2 connection is released on a particular interface and no longer can transmit Layer 3 packets.

The first SIP terminal 10 notifies the order of the preferred candidate mobile networks for handover based on the received MIH_Get_Information Response and transmits a MIH_MN_HO_candidate_Query Request to the serving PoA 41 in order to obtain the resource status of each candidate mobile network (S204). ).

Here, in the first embodiment of the present invention with reference to FIG. 2, the case where there is one candidate mobile network is taken as an example.

The serving PoA 41 transmits the MIH_N2N_HO_Query Resource Request requesting the resource status information to the candidate PoA 42 in response to the received MIH_MN_HO_candidate_Query Request (S205), and the MIH_N2N_HO_Query Resource Response including the resource status information of the candidate PoA 42. (S206). The serving PoA 41 then provides the first SIP terminal 10 with a MIH_MN_HO_candidate_Query Response including resource status information of the candidate PoA 42 in response to the MIH_MN_HO_candidate_Query Request (S207).

The first SIP terminal 10 selects a network having the best resource situation (ie, the best call quality) among the resource situations for the candidate PoA provided from the serving PoA 41 (here, corresponds to the candidate PoA 42). The MIH_MN_HO_commit Request for requesting handover to the selected network, that is, the candidate PoA 42, is transmitted through the serving PoA 41 (S208 and S209).

Then, if the candidate PoA 42 can accommodate the handover of the first SIP terminal 10, and transmits the MIH_MN_HO_commit Response to the first SIP terminal 10 via the serving PoA 41 (S210, S211).

Accordingly, the first SIP terminal 10 releases the L2 (Layer 2) link with the serving PoA 41 and connects the candidate PoA 42 with the new L2 link (S212). That is, the first SIP terminal 10 performs the handover of the L2 layer.

In the MIH function of the SIP terminal 10, Link_up is generated (S213), and a new IP is generated using address setting information included in the RtAdv (Router Advertisement) received from the candidate PoA 42 (S214, S215). .

Here, Link_up occurs when L2 layer connection is established on a specific link interface and L3 layer packets can be transmitted from a higher layer, and it is determined that all L2 layer configurations constituting the link are completed. RtAdv is a message sent from the subnet to the mobile node and acts as a trigger for handover.

When the first SIP terminal 10 generates an IP address according to address auto-configuration in step S215, the first SIP terminal 10 notifies the candidate PoA 42 of the generated IP address for DAD checking on the generated IP address. The IP address generated from the candidate PoA 42 is used to perform a DAD check for permission to use (S216).

Automatic generation of IP addresses includes a stateful address autoconfiguration method for obtaining an address using a server such as DHCP and a stateless address autoconfiguration method for generating an address by the host.

In the stateful address autoconfiguration method, when a host requests an address from a DHCP server, the server assigns one of the assignable addresses to the host and does not require DAD checking. A stateless address automatic configuration method is called a stateless address configuration method, and generates an address by combining its interface ID information with prefix information or well-known prefix information obtained from a router. This stateless address autoconfiguration method requires DAD checking after generating an IP address. The IETF RFC 2461 defines an IPv6 stateless address autoconfiguration method in which only nodes connected directly to each other in an IPv6 wired network exchange information to set a unique address, and the method for automatically configuring a stateless address according to the present invention follows.

On the other hand, if a new IP address is set through the DAD check, the first SIP terminal 10 allocates and uses the set IP address to the network interface, and notifies the upper layer, that is, the IP address set to the SIP.

Accordingly, the SIP of the first SIP terminal 10 performs a SIP handover process using the newly set IP address. That is, the first SIP terminal 10 performs the handover of the L3 layer.

That is, the SIP of the first SIP terminal 10 generates a SIP Re-INVITE message using the newly set IP address and makes a handover request to the second SIP terminal 20 (S217). 20) and the multimedia communication is resumed in response to the handover acceptance (S218 to S220).

Thereafter, the first SIP terminal 10 generates a SIP REGISTER message based on the newly set IP address, registers the newly set IP address with the SIP server 30 (S221 to S224), and then serves with the candidate PoA 42. The PoA 41 is notified of the handover completion (S225 to S228).

However, in the fast handover method using the MIH-based SIP according to the first embodiment of the present invention, the DAD check (S216) is performed after the link layer connection to the new network. Since it is performed after the process of connecting the L2 link (S212), even if the link is established to the new network, there is a problem that the SIP handover procedure must be performed after waiting a considerable time for the DAD check.

Hereinafter, a fast handover method using MIH based SIP according to a second embodiment of the present invention will be described with reference to FIG. 3. 3 is a data flow diagram illustrating a fast handover method using a MIH-based SIP according to a second embodiment of the present invention, in which a network predominantly performs a fast handover using a MIH-based SIP instead of the mobile terminal 10. It is about the case.

As shown in FIG. 3, during communication with the first SIP terminal 10 and the second SIP terminal 20, the serving PoA 41 predicts the movement of the first SIP terminal 10 using the link layer information. That is, it predicts Link_Going_Down occurrence (S301), and transmits MIH_Get_Information Request to IS (Information Server) 40) to obtain characteristic information of the candidate mobile network located around the first SIP terminal 10 (S302). In response to the received signal, the IS server 40 provides the serving PoA 41 with a MIH_Get_Information Response including characteristic information of the candidate mobile network (S303).

The serving PoA 41 provides the characteristic information of the candidate mobile network to the first SIP terminal 10 through the MIH_Net_HO_candidate_Query Request (S304), and the first SIP terminal (through the MIH_Net_HO_candidate_Query Response received from the first SIP terminal 10). 10) grasp the order of the preferred network (S305).

Then, the serving PoA 41 transmits MIH_N2N_HO_Query Resource Request to the candidate mobile network in order to grasp the network resource situation in order of the network preferred by the first SIP terminal 10 (S306), and from each candidate mobile network. MIH_N2N_HO_Query Resource Response, which is a response message thereof, is received (S307).

In FIG. 3, one candidate mobile network is used as an example, and the candidate mobile network is the second subnet N2.

The serving PoA 41 determines the handover to the candidate PoA 42 by grasping the resource status of the candidate PoA 42 through the MIH_N2N_HO_Query Resource Response received from the candidate mobile network (S308). If there are a plurality of candidate mobile networks, the serving PoA 41 determines the target mobile network to hand over the one with the best resource situation among the resource conditions of each candidate mobile network.

When the handover to the candidate PoA 42 is determined, the serving PoA 41 transmits the MIH_N2N_HO_commit Request requesting the handover to the candidate PoA 42 (S309), and the candidate PoA 42 starts with the first SIP terminal ( If the handover of 10) can be accommodated, a MIH_N2N_HO_commit Response is received from the candidate PoA 42 (S310).

Then, the serving PoA 41 informs the first SIP terminal 10 of the handover decision to the candidate PoA 42 through the MIN_Net_HO_commit Request (S311), and the MIN_Net_HO_commit Response, which is the response, from the first SIP terminal 10. Receive (S312).

The first SIP terminal 10 instructed to handover to the candidate PoA 42 connects the candidate PoA 42 with a new L2 link (S313). In the MIH function of the first SIP terminal 10, Link_up occurs (S314), and a new IP is generated using address setting information included in the RtAdv (Router Advertisement) received from the candidate PoA 42 (S315, S316).

At this time, when the first SIP terminal 10 generates an IP address according to address auto-configuration in step S215, the IP address generated for the DAD check on the generated IP address is transmitted to the candidate PoA 42. The DAD check is performed to notify the license and to use the IP address generated from the candidate PoA 42 (S316).

When the IP address is newly set through the DAD check, the first SIP terminal 10 allocates and uses the set IP address to the network interface and informs the upper layer, that is, the IP address set to the SIP. Accordingly, the SIP of the first SIP terminal 10 performs a SIP handover process using the newly set IP address.

That is, the SIP of the first SIP terminal 10 generates a SIP Re-INVITE message using the newly set IP address and makes a handover request to the second SIP terminal 20 (S317). 20) and the multimedia communication is resumed with the handover approval (S318 to S320).

Thereafter, the first SIP terminal 10 generates a SIP REGISTER message based on the newly set IP address, registers the newly set IP address with the SIP server 30 (S321 to S324), and serves with the candidate PoA 42. The PoA 41 is notified of the handover completion (S325 to S328).

However, the fast handover method using the MIH-based SIP according to the second embodiment of the present invention is performed after the link layer connection (S313) to the new network (S313) as in the first embodiment, Even if a link is established to a new network, there is a problem of waiting for a considerable time for DAD checking and then performing a SIP handover procedure.

Hereinafter, a fast handover method using MIH-based SIP according to a third embodiment of the present invention, which solves the problem of the first embodiment of the present invention. FIG. 4 is a data flow diagram illustrating a fast handover method using MIH based SIP according to a third embodiment of the present invention, which is modified from FIG. 2. 4 illustrates an example of an automatic stateless address setting method, and an example of two candidate mobile networks.

As shown in FIG. 4, when the first SIP terminal 10 detects Link_Going_Down occurrence through the MIH function during communication with the second SIP terminal 20 (S401), the MIS_Get_Information is transmitted to the information server (IS) 40. The request is transmitted (S402), and the MIH_Get_Information Response including the characteristic information of the candidate mobile network is received from the IS server 40 (S403).

At this time, MIH_Get_Information Response includes identification information and access information of a candidate mobile network (eg, PoA) around the first SIP terminal 10, an automatic address generation method for each candidate mobile network (eg, stateful address automatic setting method, and stateless type). One method of automatic address setting) and IP prefix information for each candidate mobile network are included.

Then, the first SIP terminal 10 generates a new IP address by using the corresponding IP prefix according to the address automatic generation method for each candidate mobile network included in the received MIH_Get_Information Response (S404).

Therefore, the number of newly generated IP addresses is directly proportional to the type of candidate mobile network. That is, the number of newly generated IP addresses becomes three different when there are three types of candidate mobile networks, and two different numbers when two types of candidate mobile networks exist.

The first SIP terminal 10 generates candidate IP address list information using the newly generated IP addresses, and the candidate IP address list is added to the MIH_MN_HO_candidate_Query Request requesting resource status of each candidate mobile network as shown in FIG. After including it and transmitting to the serving PoA (41) (S405).

FIG. 7A shows the data format of MIH_MN_HO_candidate_Query Request. In FIG. 7C, Dest. ID is identification information of a MIHF to be a destination of a corresponding message, Cur.Link ID is an identifier of a current link, and Candid. The Link List is a PoA list of candidate mobile networks for handover. Query Resrc.List is a resource list for identifying in the candidate mobile network, and Candid.IP Addr.List is a candidate IP address list.

Here, Candid. IP Addr.List is a proposed parameter for DAD checking of the present invention and has a format form shown in FIG. Referring to FIG. 6, the candidate IP address list indicates that the message type is for supporting DAD checking as the Support DAD, and the newly generated IP address is recorded in the NCoA. Here, NCoA (New Care of Address) represents a temporary address of a SIP terminal in a corresponding subnet.

IP Config Method indicates an address automatic configuration method, DHCP indicates a Dynamic Host Configuration Protocol (DHCP) server address, FA indicates a foreign agent address when the first SIP terminal 10 uses Mobile IP, AR Denotes an address of an AR (Access Router) when the first SIP terminal 10 uses IPV6.

Returning, when the serving PoA 41 receives the MIH_MN_HO_candidate_Query Request, it identifies each candidate mobile network, that is, the first candidate PoA 42 and the second candidate PoA 43, and each candidate PoA 42, in the candidate IP address list. Identify the newly created IP address corresponding to 43).

Subsequently, the serving PoA 41 requests a network resource status and creates a MIH_N2N_HO_Query Resource Request for each candidate PoA 42 and 43 for the newly generated IP address (S406, 43). S409).

In this case, the MIH_N2N_HO_Query Resource Request transmitted to the first candidate PoA 42 includes a first candidate IP address list including an IP address generated using the IP prefix of the first candidate PoA 42 as shown in FIG. Included. In addition, the MIH_N2N_HO_Query Resource Request transmitted to the second candidate PoA 43 includes a second candidate IP address list including an IP address generated by using the IP prefix of the second candidate PoA 43 as shown in FIG. Is included. 7B is a data format of MIH_N2N_HO_Query Resource Request.

Accordingly, each candidate PoA 42 or 43 receiving the MIH_N2N_HO_Query Resource Request performs a DAD check on the newly generated IP address included in the candidate IP address list while checking its network resource status (S407 and S410).

Then, each candidate PoA (42, 43) is included in the MIH_N2N_HO_Query Resource Response and sent to the serving PoA 41 as shown in (c) of FIG. 7 together with a report on the resource situation (S408). The serving PoA 41 collects the report on the resource status of the first and second PoAs 42 and 43 and the result of the DAD check and provides the MID_MN_HO_candidate_Query Request to the first SIP terminal 10 (S412). .

FIG. 7C is a data format of MIH_N2N_HO_Query Resource Response, and FIG. 7D is a data format of MIH_MN_HO_candidate_Query Request. In (c) and (d) of FIG. 7, a Prefered Link List indicates a link list capable of accessing a corresponding PoA, Available Resrc.Set indicates a network resource status, and IP addr.info. Is a DAD check result.

When the first SIP terminal 10 determines that the DAD check is successful through the MIH_MN_HO_candidate_Query Request, the handover of one candidate PoA having the best DAD check and the best resource condition among the network resources of each candidate PoA 42 and 43 is performed. 4, the MIH_MN_HO_commit Request requesting a handover to the first candidate PoA 42 is transmitted through the serving PoA 41 (S413 and S414). .

Then, the first candidate PoA 42 transmits the MIH_MN_HO_commit Response to the first SIP terminal 10 through the serving PoA 41 if it can accept the handover of the first SIP terminal 10 (S415, S416). .

Accordingly, the first SIP terminal 10 releases the L2 (Layer 2) link with the serving PoA 41 and connects the first candidate PoA 42 with the new L2 link (S417). Next, the MIH function of the SIP terminal 10 generates Link_up (S418).

When Link_up occurs, as in the first and second embodiments, the first SIP terminal 10 sets the newly generated IP address as the IP address to be actually used for handover to the first candidate PoA 42 (S419). .

When the new IP address is set as described above, the first SIP terminal 10 reconnects with the second SIP terminal 20 using the newly set IP address (S420). That is, handover of the L2 layer is performed.

When handover of the L2 layer is performed, the first SIP terminal 10 performs SIP handover. Since the SIP handover is the same as the steps S217 to S228 and S317 to S328 of the first and second embodiments, it will not be described further. .

On the other hand, in the DAD check, each candidate PoA (42, 43) informs MIH_MN_HO_candidate_Query Response of the IP address of the DHCP server if the automatic address setting method is changed to the DHCP server setting method. Accordingly, the first SIP terminal 10 generates an IP address by changing the method of automatically generating an address from the stateless auto configuration method to the DHCP method. The same is true when the address autoconfiguration method is changed from the DHCP method to the stateless auto configuration method in the DAD check.

In addition, in the DAD check, each candidate PoA 42 or 43 generates a new IP address using the same address auto-configuration method or changes the address auto-configuration method to DHCP if the DAD test results fail. In this case, when the automatic address setting method is changed to the DHCP method, the changed address automatic setting method is included in the MIH_MN_HO_candidate_Query Response. Accordingly, the first SIP terminal 10 generates an IP address by changing the method of automatically generating an address from the stateless auto configuration method to the DHCP method.

If there are a plurality of candidate PoAs, the following DAD checking process and candidate PoA setting process may be performed.

First, if all of the candidate PoAs fail the DAD check, an IP address is generated for all candidate PoAs using an automatic address setting method using a new DHCP server.

Second, if the DAD check succeeds in at least one candidate PoA, handovers one candidate PoA with good resource status among the candidate PoAs that succeeded in the DAD check without generating an IP address or performing a DAD check for the candidate PoA that failed the DAD check. Decide on PoA to do

Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG. 5. FIG. 5 is a data flow diagram illustrating a fast handover method using MIH based SIP according to the fourth embodiment of the present invention, which is modified from FIG. 3.

As shown in FIG. 5, during communication with the first SIP terminal 10 and the second SIP terminal 20, the serving PoA 41 predicts the movement of the first SIP terminal 10 using link layer information. Then, the MIH_Get_Information Request is transmitted to the information server (IS) 40 (S501), and the MIH_Get_Information Response including the characteristic information of the candidate mobile network is received from the IS server 40 (S502). MIH_Get_Information Responset includes identification information of candidate mobile networks (eg, PoA) around the first SIP terminal 10, automatic address generation method for each candidate mobile network (eg, stateful address automatic setup method, and stateless address automatic setup method). ), And IP prefix information for each candidate mobile network.

Then, the serving PoA 41 transmits MIH_N2N_HO_Query Resource Request to the first SIP terminal 10 in order to grasp the information of the network preferred by the first SIP terminal 10 (S503), and the first SIP terminal 10 MIH_Net_HO_candidate_Query Response is received from step S504.

When the serving PoA 41 receives the MIH_MN_HO_candidate_Query Response, the serving PoA 41 generates a new IP address using the corresponding IP prefix according to the address automatic generation method for each candidate mobile network (S505). The number of newly created IP addresses is directly proportional to the type of candidate mobile network.

The serving PoA 41 then uses the respective IP addresses generated for each candidate mobile network, i.e., the first candidate PoA 42 and the second candidate PoA 43, respectively to list candidate IP addresses that are new parameters of the MIH. Then, it requests the network resource status as shown in FIG. 7 (b) and includes it in the MIH_N2N_HO_Query Resource Request informing of the newly generated IP address and transmits it to each candidate PoAs 42 and 43 (S506 and S509).

Accordingly, the MIH_N2N_HO_Query Resource Request transmitted to the first candidate PoA 42 includes the first candidate IP address list including the IP address generated by using the IP prefix of the first candidate PoA 42 as shown in FIG. Is included. In addition, the MIH_N2N_HO_Query Resource Request transmitted to the second candidate PoA 43 includes a second candidate IP address list including an IP address generated by using the IP prefix of the second candidate PoA 43 as shown in FIG. Is included. 7B is a data format of MIH_N2N_HO_Query Resource Request.

In response to the MIH_N2N_HO_Query Resource Request, each candidate PoA 42 or 43 performs a DAD check on the newly generated IP address included in the candidate IP address list while checking its network resource status (S507 and S510).

Then, each of the candidate PoAs 42 and 43 includes the DAD check result along with the report on the resource status and transmits the result of the DAD check to the serving PoA 41 by including it in the MIH_N2N_HO_Query Resource Response as shown in FIG. In operation S512, the serving PoA 41 determines a target, that is, a candidate PoA, by hand, by grasping the report on the resource status of the first and second PoAs 42 and 43 and the result of the DAD check.

In step S512, if the serving PoA 41 determines that the DAD check is successful through the MIH_MN_HO_candidate_Query Request, the serving PoA 41 handles one candidate PoA having the best DAD check and the best resource condition among the network resources of the candidate PoAs 42 and 43. It is determined as the network to be over (referred to as the first PoA 42 in FIG. 5), and the MIH_N2N_HO_commit Request for requesting handover to the first candidate PoA 42 is transmitted through the serving PoA 41 (S513).

Then, the first candidate PoA 42 transmits the MIH_N2N_HO_commit Response to the serving PoA 41 if it can accept the handover of the first SIP terminal 10 (S514).

When the serving PoA 41 receives the MIH_N2N_HO_commit Response, the serving PoA 41 notifies the first SIP terminal 10 of the handover decision to the first candidate PoA 42 through the MIN_Net_HO_commit Request (S515), and the first SIP terminal. The MIN_Net_HO_commit Response, which is the response, is received from (10) (S516).

The first SIP terminal 10 instructed to handover to the first candidate PoA 42 connects the new candidate PoA 42 with a new L2 link (S517). In the MIH function of the SIP terminal 10, Link_up occurs (S518), and the newly generated IP address corresponding to the first candidate PoA 42 is set as an IP address to be used for communication with the first candidate PoA 42. (S519).

When the new IP address is set as described above, the first SIP terminal 10 reconnects to the second SIP terminal 20 using the newly set IP address (S520). That is, the first SIP terminal 10 performs the handover of the L2 layer.

When the L2 layer is handed over, the first SIP terminal 10 performs the L3 layer handover. The handover of the L3 layer is the same as that of the steps S217 to S228 and S317 to S328 of the first and second embodiments. No description above.

The embodiments of the present invention described above are not implemented only through the apparatus and the method, but may be implemented through a program for realizing a function corresponding to the configuration of the embodiment of the present invention or a recording medium on which the program is recorded. Implementation may be easily 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 showing a network environment to which the present invention is applied.

2 is a data flow diagram illustrating a fast handover method using MIH based SIP according to the first embodiment of the present invention.

3 is a data flow diagram illustrating a fast handover method using MIH based SIP according to a second embodiment of the present invention.

FIG. 4 is a data flow diagram illustrating a fast handover method using MIH based SIP according to a third embodiment of the present invention, which is modified from FIG. 2.

FIG. 5 is a data flow diagram illustrating a fast handover method using MIH based SIP according to the fourth embodiment of the present invention, which is modified from FIG. 3.

FIG. 6 is a diagram illustrating a data format of a candidate IP address list required for DAD checking in the third and fourth embodiments of the present invention.

7 illustrates a format of a message including a candidate IP address list according to an embodiment of the present invention.

Claims (14)

In the method of the mobile terminal using the Session Initiation Protocol (SIP) and Media Independent Handover (MIH) to the high-speed handover to different IP networks, A first step of generating a first IP address corresponding to each candidate mobile network in the vicinity when the mobile terminal detects a handover occurrence event; Transmitting a first IP address of the corresponding candidate mobile network generated to each candidate mobile network; Performing a redundancy check on the first IP address in each candidate mobile network and informing the mobile station of the redundancy check result; A fourth step of the mobile terminal reflecting the result of the redundancy check and determining a first candidate mobile network to hand over one candidate mobile network among the candidate mobile networks; Performing a handover of an L2 layer to the first candidate mobile network; And And performing a SIP handover using the first IP address of the first candidate mobile network as a set IP address after performing the handover of the L2 layer. Fast handover method. The method of claim 1, The first step, A fast handover method using a media independent handover based SIP to generate the first IP address according to an address automatic configuration method designated by the candidate mobile network. The method of claim 2, The automatic address setting method may include a method of receiving an IP address from a DHCP server and generating an IP address using an IP prefix provided by the corresponding candidate mobile network. Fast handover method using. The method of claim 1, In the second step, a fast handover method using a media independent handover-based SIP to transmit a first message requesting a resource situation for each candidate mobile network by including the first IP address of the candidate mobile network. . The method of claim 4, wherein The third step, Fast handover method using a media independent handover based SIP including the redundancy check result in the response message to the first message. The method of claim 5, In the third step, if the result of the redundancy check fails or the address automatic setting method is changed, the mobile terminal is notified to the mobile terminal by including the changed address automatic setting method in the response message to the first message. In this case, the mobile terminal further comprises a seventh step of generating a new second IP address according to the changed automatic address setting method using a media independent handover based SIP. The method according to claim 1 or 6, In a fourth step, a fast handover method using media independent handover based SIP to determine, as the first candidate mobile network, one candidate mobile network having the best resource situation among the candidate mobile networks having a successful redundancy check result. . In the method of the mobile terminal using the Session Initiation Protocol (SIP) and Media Independent Handover (MIH) to the high-speed handover to different IP networks, A first step of a serving point of access (POA) predicting a handover situation of the mobile terminal; Generating, by the serving PoA, a first IP address corresponding to each candidate mobile network in which the mobile station is located; Transmitting, by the serving PoA, the first IP address of the corresponding candidate mobile network generated to each candidate mobile network; Performing a redundancy check on the first IP address in each candidate mobile network and informing the serving PoA of the redundancy check result; A fourth step of the serving PoA reflecting the result of the redundancy check and determining a first candidate mobile network to handover one candidate mobile network among the candidate mobile networks; A fifth step of informing the mobile station of the determined first candidate mobile network, whereby the mobile station performs handover of an L2 layer; And And performing a SIP handover using the first IP address for the first candidate mobile network, which has been handed over by the L2 layer, as the set IP address. Fast handover method using SIP. The method of claim 8, The first step, A fast handover method using a media independent handover based SIP to generate the first IP address according to an address automatic configuration method designated by the candidate mobile network. The method of claim 9, The automatic address setting method may include a method of receiving an IP address from a DHCP server and generating an IP address using an IP prefix provided by the corresponding candidate mobile network. Fast handover method using. The method of claim 8, In the second step, a fast handover method using a media independent handover-based SIP to transmit a first message requesting a resource situation for each candidate mobile network by including the first IP address of the candidate mobile network. . The method of claim 11, The third step, Fast handover method using a media independent handover based SIP including the redundancy check result in the response message to the first message. The method of claim 12, In the third step, if the result of the redundancy check fails or the address automatic setting method is changed, the mobile terminal is notified to the mobile terminal by including the changed address automatic setting method in the response message to the first message. In this case, the serving PoA further comprises a seventh step of generating a new second IP address in accordance with the modified automatic addressing method of the media independent handover based fast handover method using SIP. The method according to claim 8 or 13, In a fourth step, a fast handover method using media independent handover based SIP to determine, as the first candidate mobile network, one candidate mobile network having the best resource situation among the candidate mobile networks having a successful redundancy check result. .

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