KR20090043411A - Apparatus and method for mobility support in wireless voip network - Google Patents

Abstract

1. TECHNICAL FIELD OF THE INVENTION

An apparatus and method for supporting mobility in a wireless VoIP network.

2. Technical problem to be solved by the invention

It solves the triangular routing problem of mobile IP and provides efficient mobility support method to prevent handoff drop and data delay.

3. Summary of Solution to Invention

Requesting arbitrary data, a mobile node whose location changes, a corresponding node capable of providing the requested data to the mobile node, obtaining information of the mobile node from the mobile node, and connecting a message between the mobile node and the corresponding node; And a home agent manager for acquiring the information of the mobile node from an external agent manager and the external agent manager, and transmitting the location information of the mobile node to the corresponding node based on a message transmitted from the corresponding node.

4. Important uses of the invention

Used in wireless VoIP networks.

Wireless, Internet, Mobility, Mobility, SIP

Description

Apparatus and Method for mobility support in wireless VoIP network

The present invention relates to an apparatus and a method for supporting mobility in a wireless VoIP network. More particularly, the present invention relates to an efficient apparatus and method for solving a triangular routing problem of mobile IP and preventing handoff disconnection and data delay. It is about.

Internet telephony service using VoIP is provided based on the high speed of the Internet, and as the VoIP service is required in the wireless network, the mobility research in the wireless network is actively conducted.

In general, since the Internet has a distributed communication network and location information is distributed around the Internet, mobility management on the Internet is not easy.

1 is a diagram illustrating an embodiment of a conventional mobile IP.

Here, the mobile IP (Internet protocol) is standardized in the Internet Engineering Task Force (IETF) to support the mobility (mobility) of the node on the Internet, so that the IP terminal can maintain a connection with the Internet network regardless of the location. (Distributed communication system)

As shown in FIG. 1, the mobile IP includes a home agent (HA) 101, an external agent (FA) 103, a mobile host (MH) 105, and a corresponding host (Corresponding Host). CH, 107).

The HA 101 manages a home network with a main server for mutual wireless communication with a mobile node. The FA 103 relays mutual wireless communication between a mobile node and a home agent and manages an external network. The MH 105 requests the required data to the CH 107, i.e. is a mobile node. The CH 107 provides the data requested from the MH 105, that is, the corresponding node.

If the MH 105 does not receive an advertising message from the HA 101, the MH 105 is determined to be in the FA 103, the MH 105 is registered with the FA 103, the FA 103 notifies the HA 101 of its temporary address (Care-Of-Address, COA).

Next, the CH 107 recognizes that the MH 105 is in the home network, and transmits data to the HA 101. The HA 101 receiving the data recognizes that the MH 105 does not exist in the home network, and uses the Binding List including the IP address. Data forwarding to 103 allows data to be sent to MH 105.

Therefore, since the data transmitted by the CH 107 is transmitted to the MH 105 through the HA 101, triangular routing occurs in the data transmission. That is, a delay time is generated.

As described above, when the conventional mobile IP is used, a problem of delay in data transmission occurs while triangular routing occurs, and location information registration of the mobile host is repeated according to a change in location, thereby causing handoff breakage and data delay.

Accordingly, there is a need for a mobility device and method for solving the data transmission delay problem caused by triangular routing of mobile IP and preventing handoff drop and data delay due to a change in position.

The present invention has been proposed to meet the above demands, and solves the problem of triangular routing of mobile IP using SIP Redirect, and supports efficient mobility to manage mobile nodes continuously changing location using cellular IP. It is an object to provide an apparatus and method.

In order to achieve the above object, the present invention provides a device for supporting mobility in a wireless VoIP network, the mobile node having a request for arbitrary data and providing the mobile node with the changed data to the mobile node. Obtains information of the mobile node from the node, obtains the information of the mobile node from the external agent management unit and the external agent management unit for connecting messages between the mobile node and the corresponding node, and based on the message transmitted from the corresponding node Provided is a mobility management device including a home agent management unit for transmitting location information of a node to a corresponding node.

The present invention provides a mobility management apparatus and method using the SIP Redirect and Cellular IP in a wireless VoIP network, it is possible to solve the triangular routing problem of mobile IP, and to prevent handoff disconnection and data delay.

The above objects, features and advantages will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an embodiment of a mobility support method according to the present invention.

As shown in FIG. 2, the present invention provides a home agent management unit (Home Agent Management (HAM) 201), an external agent domain management unit (Foreign Agent Domain Management (FADM) 203), a mobile node (Mobile Node, MN, 205), and the like. It includes a corresponding node (Corresponding Node, CN, 207).

The HAM 201 serves as a home agent managing a home network with a main server for mutual wireless communication with a mobile node, and serves as a redirect server in SIP.

Here, SIP is a Session Initiation Protocol. Like a Hyper Text Transfer Protocol (HTTP), when a client sends a service request message (INVITE message) to a server, the server completes the corresponding processing and then sends a response message. It operates in a transaction processing manner sent to a client, and SIP includes a user agent (UA), a proxy server, and a redirect server.

The proxy server transmits a connection request message sent from a UA to a proxy server or redirect server of another domain or to a UA in a corresponding domain, and manages information for billing.

The Redirect server notifies the UA or Proxy server that sent the connection request message the address of the UA or proxy server to which the connection request message should be resent, without directly forwarding the transmitted connection request message to another UA or proxy server. That is, the caller sends a session request message (INVITE) to the Redirect server in order to create a new session with Callee or to join the receiver in an existing session. Next, the Redirect server receiving the session request message sends a message 302 Move including the location information of the callee to the caller. Next, the caller who receives the location information of the callee joins the callee by sending a session request message INVITE to the callee.

The FADM 203 relays wireless communication between a mobile node and a home agent and serves as an external agent for managing an external network, serves as a proxy server in SIP, and provides location information of a mobile node whose location is constantly changing. It also serves as a cellular IP gateway in the managing cellular IP network.

Cellular IP does not burden the Internet because the mobile node does not have to inform the home agent of local movement. For optimal system operation

Cellular IP manages two mapping tables, Paging Cache (PC) and Routing Cache (RC), to manage the paging and routing processes independently. The paging cache is maintained only on a plurality of selected nodes within Cellular IP, and maintains approximate location information for mobile nodes in all states. The routing cache maintains up-to-date accurate location information for active mobile nodes.

The Cellular IP supports flexible handoff. There is no need to create, maintain, or delete a paging cache and a routing cache according to the change of state of the mobile node. That is, the paging cache timeout, routing cache timeout, paging and routing update need not be repeated to inform the change of the mobile node, and the flexible handoff can be supported by minimizing unnecessary waste of resources.

As described above, Cellular IP is very practical in supporting local mobility compared to Mobile IP even when the mobile node moves frequently.

2 again, the MN 205 is a terminal for requesting data, and the CN 207 is a server for providing the requested data from the MN 205.

3 is a flowchart illustrating an example of a mobility support method according to the present invention.

As shown in FIG. 3, first, when a beacon is received at a base station (Base-Station, BS, not shown) (s301), the MN 205 sends a Route Update packet to the BS. The BS transmits the transmitted Route Update packet to the first FADM (not shown) and the second FADM (not shown) in a hop-by-hop manner (s303a and s303b). Here, the Route Update packet includes the location of the MN 205 and uniform resource identifier (URI) information.

When the MN 205 is included in an area of a first FADM (not shown), a Route Update packet is transmitted to a first FADM (not shown), and the MN 205 is included in an area of a second FADM (not shown). In this case, a Route Update packet is transmitted to the second FADM (not shown).

During the steps s301 to s303, the MN 205 updates the routing cache between each BS and the FADM (eg, BS and first FADM (not shown), BS and second FADM (not shown)) ( s304).

Next, the first FADM (not shown) and the second FADM (not shown) transmit a SIP registrar message to the HAM 201 (s305a and s305b). Here, the SIP Registrar message includes Career Addresses (Care of Addres, CoA) of each FADM and the information of the URI of the MN 205, and the HAM 201 registers the information of the MN by using the transmitted information. Update the binding list.

Next, when the CN 207 transmits an Invite message to the HAM 201 (s306), the HAM 201 transmits the location information of the MN 205 to the CN 207 using a 302 message. (s307). That is, the HAM 201 serves as a redirect server in SIP.

Next, the CN 207 having obtained the location information of the MN 205 transmits an Invite message to a first FADM (not shown) including the MN 205 (S308). That is, the first FADM (not shown) serves as a proxy server.

Next, the first FADM (not shown) checks the destination IP address of the transmitted Invite message, compares it with its routing cache information, and transmits the Invite message to the MN 205 corresponding to the destination IP address (s309). . Here, each MN 205 can know the information of the neighbor node of each MN 205 by the beacon transmitted from the BS. That is, the first FADM (not shown) serves as a cellular IP gateway.

Next, the MN 205 receiving the Invite message transmits a 200 OK message to the BS using the neighbor node's information (s310), and the BS transmits the first FADM (hopest-based shortest path routing) to the BS. 200 OK message is sent to (s311). Here, the shortest path routing method is a shortest path setting method that is generally used.

Next, the first FADM (not shown) transmits a 200 OK message to the CN 207 (s312), and the CN 207 receiving the 200 OK message enters a media session with the MN 205. It may be transmitted (s313).

As described above, the method of the present invention may be implemented as a program and stored in a recording medium (CD-ROM, RAM, ROM, floppy disk, hard disk, magneto-optical disk, etc.) in a computer-readable form. Since this process can be easily implemented by those skilled in the art will not be described in more detail.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made in the art without departing from the technical spirit of the present invention. It will be clear to those of ordinary knowledge.

1 is a configuration diagram of an embodiment showing a conventional mobile IP.

Figure 2 is an embodiment configuration showing a mobility support method according to the present invention.

3 is a flowchart illustrating an embodiment of a mobility support method according to the present invention.

Claims (14)

In a mobility support device in a wireless VoIP network, Mobile node requesting random data and changing location Corresponding node capable of providing requested data to the mobile node Obtaining information of the mobile node from the mobile node, and an external agent management unit for connecting a message between the mobile node and the corresponding node and The home agent manager obtains the information of the mobile node from the external agent manager, and transmits the location information of the mobile node to the corresponding node based on the message transmitted from the corresponding node. Mobility management device comprising a. The method of claim 1, The home agent management unit Obtaining information of the mobile node from the external agent manager to update the binding list Mobility management device. The method of claim 2, The binding list is Auxiliary address of external agent management unit and URI information of the mobile node Mobility management device comprising a. The method of claim 1, The home agent management unit SIP redirect server Mobility management device. The method of claim 1, The external agent management unit SIP's proxy server Mobility management device. The method of claim 1, The external agent management unit Cellular IP's Cellular IP gateway, Mobility management device. The method of claim 1, The information of the mobile node Contains location information and URI information of mobile node Mobility management device. In the mobility support method in a wireless VoIP network, The first step in which the home agent manager acquires the information of the mobile node from the mobile node A second step of transmitting, by the home agent manager, location information of the mobile node to the corresponding node based on the message transmitted from the corresponding node; A third step of the corresponding node transmitting a message to an agent manager using location information of the mobile node; and A fourth step of connecting the corresponding node and the mobile node through the external agent manager; Mobility management method comprising a. The method of claim 8, The first step is Acquiring the information of the mobile node to update the binding list How to manage mobility. The method of claim 9, The binding list is Auxiliary address of external agent management unit and URI information of the mobile node Mobility management method comprising a. The method of claim 8, The home agent management unit SIP redirect server How to manage mobility. The method of claim 8, The external agent management unit SIP's proxy server How to manage mobility. The method of claim 8, The external agent management unit Cellular IP's Cellular IP gateway, How to manage mobility. The method of claim 8, The information of the mobile node Contains location information and URI information of mobile node How to manage mobility.

Images