KR100980582B1 - A Scheme of SCTP Handover with Bicasting for mobile Internet Service - Google Patents

Abstract

The present invention relates to a bicasting-based SCTP handover method in a wireless Internet environment which reduces the possibility of data loss and handover delay, and a mobile terminal performing the same. When entering a second IP network and obtaining a new IP address from the second IP network, the mobile terminal and the counterpart node transmit and receive data by simultaneously using the acquired new IP address and the existing IP address used in the first IP network. If the mobile terminal leaves the first IP network while performing the bicasting, the mobile terminal deletes the existing IP address and performs data communication using only the new IP address.

Hand-over, bicasting, SCTP, wireless Internet, IP address

Description

Bicasting based SCTP handover method and mobile terminal in wireless Internet environment {A Scheme of SCTP Handover with Bicasting for mobile Internet Service}

The present invention relates to a handover method that enables seamless data communication even after a mobile terminal in data communication moves to an area of a new IP network. More particularly, the present invention relates to a wireless Internet capable of minimizing handover delay and data loss. The present invention relates to a bicasting-based SCTP handover method in an environment and a mobile terminal performing the same.

1 illustrates a schematic structure of a wireless Internet system, in which a mobile terminal 11 that is located in an area of a first IP network and is in data communication with a counterpart node 14 through a first access router 12a moves by a user. When the mobile terminal 11 moves to the area of the second IP network according to the present invention, the mobile terminal 11 disconnects the wireless connection with the first access router 12a in order to continue communication with the counterpart node 14 and is located in the second IP network. 2 A wireless connection must be made with the access router 12b. Here, the data transmission path through the first access router 12a should be switched to the data transmission path through the second access router 12b. This process is referred to as handover.

This handover process is preferably performed quickly while reducing the data loss rate.

2 is a flowchart illustrating a handover method in a stream control transmission protocol (SCTP) as an example of a conventional handover method.

Referring to FIG. 2, conventionally, the mobile terminal 11 enters the second IP network while performing data communication with the counterpart node 14 via the first access router 12a in the first IP network (S21). If so, the mobile terminal 11 obtains a new address through the second access router 12b located in the second IP network (S22).

In order to inform the counterpart node 14 of the acquired new address, a message for requesting the addition of a new address is sent to the counterpart node 14 (S23), and a response message for the new address add request from the counterpart node 14 is sent. Receive (S24). At this time, the partner node 14 knows the new IP address, but cannot use the new IP address as the data transmission path until the switching of the data transmission path is completed.

That is, the mobile terminal 11 notifies the counterpart node 14 of the new IP address, and then performs a handover procedure of the link layer with the second access router 12b (S25), thereby communicating with the second IP network. When the link layer connection is established, a request message is sent to the counterpart node 14 to switch the data transmission path (S26).

 The counterpart node 14 having received the request message for switching the data transmission path sends a response message to the mobile terminal 11 to accept the request.

Accordingly, the main data transmission path of the mobile terminal 11 is changed to a new IP address, and data transmission and reception using the new IP address is performed between the mobile terminal 11 and the counterpart node 14 (S28). .

When the mobile terminal 11 completely leaves the area of the existing first IP network, the mobile terminal 11 transmits a request message for deleting the existing IP address to the counterpart node 14 (S29). In response, the counterpart node 14 transmits the response message to the mobile terminal 11 after the deletion process of the existing IP address.

However, in the conventional method, since the data transmission path is switched after performing the handover at the link layer, a relatively long handover delay occurs.

Furthermore, if a data transmission path is changed after a considerable time has elapsed after performing the link layer handover, the delay is further increased by the time difference between the handover time of the link layer and the time point of the data transmission path.

In addition, data loss may occur when the mobile terminal leaves the previous IP network before the data transmission path is established.

The present invention has been proposed to reduce the possibility of data loss and handover delay in the existing handover process. When a new IP address is obtained, the same data is transmitted and received using the existing IP address and the new IP address. The present invention provides a bicasting-based SCTP handover method in a wireless Internet environment that minimizes the possibility of data loss and handover delay, and a mobile terminal performing the same.

As a means for solving the above problems, according to an embodiment of the present invention, in the bicasting-based SCTP handover method in a wireless Internet environment, a mobile terminal in data communication with a counterpart node through a first IP network is connected to a second IP. Confirming whether or not to enter the network; If it is confirmed that the mobile terminal has entered the second IP network, the mobile terminal obtaining a new IP address from the second IP network; Bicasting data between the mobile terminal and the counterpart node using the acquired new IP address and the existing IP address used in the first IP network at the same time; Checking whether the mobile terminal deviates from the first IP network while performing the bicasting; And if it is confirmed that the mobile terminal deviates from the first IP network, the mobile terminal and the counterpart end the bicasting and perform data communication using only the new IP address.

In the handover method of the present invention, the bicasting may include: transmitting a request message for adding a new IP address to the counterpart node, including whether the mobile terminal performs bicasting; Receiving a response message including whether to accept the bicasting from the counterpart node; And performing bicasting between the mobile terminal and the counterpart node when the counterpart node accepts the bicasting.

Further, in the handover method of the present invention, whether or not to perform the bicasting and whether to accept the bicasting is characterized in that the bicasting flag set in the flag field of the message transmitted between the mobile terminal and the counterpart node.

Further, in the handover method of the present invention, terminating the by-casting and performing data communication with a new IP address only, if it is confirmed that the mobile terminal deviates from the first IP network, deleting the existing IP address to the counterpart node. Sending a request message; Receiving, by the mobile terminal, a response message for a request for deleting an existing IP address from a counterpart node; And upon receiving the response message, terminating bicasting.

In addition, according to another embodiment of the present invention, a mobile terminal according to the present invention, the mobility detection unit for detecting whether the mobile terminal enters or leaves the existing IP network; An address obtaining unit obtaining a new IP address from the new IP network when the mobility detection unit detects an entry into a new IP network; When the mobility detection unit detects an entry into a new IP network, an additional request message of a new IP address including whether to perform bicasting is transmitted to a counterpart node, and when a departure from the existing IP network is detected, a request for deleting an existing IP address Handover management unit for transmitting to the counter node; And by-casting performing unit for transmitting and receiving data using the new IP address and the existing IP address obtained from the address acquisition unit at the same time.

In the mobile terminal according to the present invention, the handover management unit determines whether to accept the bicasting of the counterpart node, and controls the bicasting performing unit to operate when the bicasting is accepted, and determines the existing IP address from the counterpart node. When a response to the deletion request is received, the bicasting is terminated.

In addition, in the mobile terminal according to the present invention, when the handover management unit receives a new IP address addition request message including whether to perform bicasting from the counterpart node, it determines whether to accept the bicasting and responds to the counterpart node, Controls the by-casting execution unit that transmits and receives data through the existing IP address and the newly requested new IP address, and deletes the existing IP address when receiving a request for deleting the existing IP address from the counterpart node when performing the bicasting. And control the bicasting to be terminated.

According to the above configuration, in the present invention, after the mobile terminal enters a new IP network and acquires a new IP address, the handover procedure of the link layer is completed and the mobile terminal and the counterpart node until the mobile terminal leaves the previous IP network. By allowing data to be transmitted using both the old and new IP addresses, the long handover delay can be reduced, thereby eliminating the possibility of data loss during the handover delay.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing in detail the operating principle of the preferred embodiment of the present invention, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings.

In addition, throughout the specification, when a part is 'connected' to another part, it is not only 'directly connected' but also 'indirectly connected' with another element in between. Include. In addition, the term 'comprising' a certain component means that the component may be further included, without excluding the other component unless specifically stated otherwise.

In addition, the components for handover processing of the mobile terminal according to the present invention are shown separately by specific functions or operations, and may be implemented by hardware or software or a combination of hardware and software.

3 is a flowchart illustrating an SCTP handover process to which the present invention is applied.

According to the present invention, while the mobile terminal 11 performs data communication with the counterpart node 14 via the first access router 12a in the first IP network (S31), entry into the second IP network is confirmed. If a new address is obtained from the second access router 12b located in the second IP network (S32), the partner node receives a message requesting addition of a new address to inform the counterpart node 14 of the acquired new address. Send to 14 to receive the response message (S33, S34).

In addition, the mobile terminal 11 transmits and receives data using both the existing node 14 and the new IP address acquired from the first IP network and the new IP address acquired from the second IP network (S35 and S37). .

And, while the data transmission through the bi-casting is performed, the mobile terminal 11 performs a handover of the link layer (S36), after the handover of the link layer is completed, the mobile terminal 11 is the first IP Once completely out of the network area, the counterpart node 14 requests deletion of the existing IP address (S38) and receives a response to the request for deleting the existing IP address (S39).

When the steps S38 and S39 are normally completed, since the existing IP address is deleted, data transmission through bicasting is stopped and data is transmitted and received using only the new IP address (S40).

That is, when the mobile terminal 11 is located in the first IP network area, data transmission is performed through the existing IP address, and the existing IP address and the new IP address in the overlapping section of the first IP network and the second IP network. When data communication is performed by low-by-casting, and completely moves out of the first IP network to the second IP network, data communication is performed only through the new IP address.

According to this, after the new IP address is allocated, the possibility of data loss is eliminated by transmitting and receiving the same data to the two IP addresses until the handover is completed. As soon as the connection between the IP network and the link layer is established, data can be transmitted and received through the new IP address. According to this, since the main data transmission path switching process is unnecessary, the handover delay time becomes purely the handover delay time of the link layer.

For the above handover process, in the present invention, when sending a message requesting the addition of a new IP address in step S33 and a response message for the request for adding the IP address, whether or not to perform bicasting is accepted. Send information indicating whether or not. Whether or not to perform the bicasting can be displayed as shown in FIG.

4 is an SCTP message structure diagram according to the present invention for sending bicasting information.

In general, an SCTP packet is formed by placing a plurality of chunks for transmitting a control message and data after a common header including source port and destination port. It is divided into control chunks for connection establishment, release, and error transmission, data chunks for data transmission, and sack chunk for response. Each chunk includes a Type for distinguishing whether it is a control message, data, or response, Flags, a Length indicating the length of the chunk, and other control information. The message format of FIG. 4 illustrates a message structure of a chunk included in the SCTP packet.

In an embodiment of the present invention, as shown in FIG. 4, in the flags field (Flags) in the chunk of the SCTP packet, one bit is used as a bicasting flag, and the bicasting is performed using the bicasting flag. Whether to perform casting and whether to accept bicasting is transmitted.

Next, FIG. 5 is a flowchart illustrating a handover process performed in the mobile terminal 11 in detail.

Referring to FIG. 5, the mobile terminal 11 performing data communication through the first IP network always detects whether a new IP network or a second IP network has been moved (S51).

In the above, if it is confirmed that the move to the second IP network, the mobile terminal 11 obtains a new IP address from the second IP network (S52).

The movement detection to the new IP network and the acquisition of a new IP address may be performed by using various well-known methods, and the present invention is not related to the movement detection and IP address allocation itself. Is omitted.

When a new IP address is obtained in step S52, the mobile terminal 11 notifies the counterpart node 14 of the obtained new IP address (S53). The step S53 may be performed by sending a message requesting the addition of a new IP address. Here, the mobile terminal 11 may separately indicate whether to perform the bicasting using the new IP address. That is, as shown in FIG. 4, when the bicasting flag is set to "1" in the message requesting the addition of the new IP address, the bicasting request is requested, and the bicasting flag is set to "0". You can set it to not request bicasting. When bicasting is not requested, processing may be performed according to an existing handover procedure.

As described above, the mobile terminal 11 notifying the counterpart node 14 of the new IP address starts transmitting and receiving data to the new IP address as well as the existing IP address through bicasting (S54). Here, the data transmission and reception will be performed using only the existing IP address until the link layer connection in the second IP network is completed, and when the link layer connection in the second IP network is completed, the data is transmitted to the new IP address as well as the existing IP address. Transmission and reception can be made. The step S54 may be executed according to whether the partner node 14 accepts the bicasting. More specifically, the partner node 14 determines the acceptance of the partner node 14 by checking the bicasting flag inserted in the response message for the addition request of the new IP address transmitted from the partner node 14, and the partner node 14 accepts the request. Only one case may be to perform the step (S54).

While the above-mentioned bicasting is performed, the mobile terminal 11 may perform handover of the link layer according to the SCTP procedure.

In addition, the mobile terminal 11 checks whether the existing IP network, that is, the area of the first IP network, is left while the bicasting is being performed (S55).

As a result of the check, if the area of the first IP network is completely removed, the mobile terminal 11 notifies the relative node 14 of the deletion of the existing IP address (S56). More specifically, it sends a delete request message of an existing IP address and receives a response from the counterpart node 14 thereto.

Thereafter, the existing IP address is deleted, and data communication is performed between the mobile terminal 11 and the counterpart node 14 only using the new IP address (S57).

FIG. 6 is a flowchart showing the processing procedure in the counterpart node 14 corresponding to the processing of the mobile terminal 11 described above.

Referring to FIG. 6, when the counterpart node 14 receives a request for adding a new IP from the mobile terminal 11 while performing data communication with the mobile terminal 11 (S61), the counterpart node 14 requests the addition of the new IP. After the transmission, the response is transmitted to the mobile terminal 11 (S62). In this case, as shown in FIG. 4, the request message for adding a new IP address may have a by-casting flag inserted. In this case, the counterpart node 14 checks the by-casting flag and requests that the by-casting is requested. And, if requested, may decide to accept bicasting. Whether to accept the bicasting may be indicated in the response message for the request for adding the new IP address as shown in FIG. 4. In this case, when the counterpart node 14 refuses to perform the bicasting, processing may be performed according to an existing handover procedure, and the counterpart node 14 marks the bicasting in a response message for the addition request of the new IP address. You can send it without inserting it, or send an error message as a response.

When accepting the bicasting, the counterpart node 14 performs data communication with the mobile terminal 11 by bicasting by using the new IP address of the mobile terminal 11 and the existing IP address together (S63). .

Here, the step S63 may be performed only when there is a bicasting mark in the addition request message of the new IP received in the step S62 and the counterpart node 14 accepts it.

During the bicasting as described above, if a request for deleting an existing IP address is received from the mobile terminal 11 (S64), the counterpart node 14 deletes the existing IP address and then transfers the existing IP address to the mobile terminal 11. In response to the request for deleting the IP address, a response message is sent (S65).

Thereafter, since the existing IP address is deleted, data communication is performed with the mobile terminal 11 using only the new IP address (S66).

In addition, the counterpart node 14 may be a server or a terminal connected online, or may be a mobile terminal of another user. That is, the process illustrated in FIG. 6 may be performed in the mobile terminal.

7 is a block diagram showing the configuration of a mobile terminal for performing the handover method according to the present invention.

Referring to FIG. 7, the mobile terminal according to the present invention includes a mobility detector 71, an address acquirer 72, a handover manager 73, and a bicasting performer 74.

The mobility detector 71 detects whether the mobile terminal enters a new IP network or leaves an existing IP network.

When the mobility detector 71 detects an entry into a new IP network, the address obtainer 72 obtains a new IP address from the entered new IP network, and the handover manager 73 and the bicasting performer. Provided at 74.

When the new IP address is acquired by the address obtaining unit 72, the handover manager 73 notifies the counterpart node of the new IP address through an SCTP message, and receives and processes a response message. In addition, when the mobile terminal detects that the mobile terminal deviates from the existing IP network, the mobility detector 71 requests the counterpart node to delete the existing IP address used in the existing IP network and receives and processes a response message. . At this time, the handover manager 73 inserts a by-casting flag requesting by-casting in a new IP address addition request message transmitted and received with the counterpart node. In addition, the bicasting execution unit 74 may be controlled according to whether to accept the bicasting from the counterpart node.

The by-casting performing unit 74 receives the new IP address obtained from the address obtaining unit 72 and performs the by-casting according to the control of the handover managing unit 73 to obtain the obtained new IP address and Send and receive data simultaneously to an existing IP address.

In addition, when the mobile terminal illustrated in FIG. 7 operates as the counterpart node 14 of FIG. 1, the handover manager 73 receives a new IP address addition request message in which a by-casting flag is inserted from another mobile terminal. Upon reception, it adds the new IP address and determines whether to accept the bicasting and transmits the response message with the bicasting flag inserted. Then, the by-casting performing unit 74 is controlled to perform data transmission and reception simultaneously with the existing IP address and the newly requested new IP address.

In addition, the handover manager 73 deletes the existing IP address when receiving the delete request message of the existing IP address from another mobile terminal while performing the bicasting, and performs the bycasting performing unit 74. By controlling, bicasting is terminated. When bicasting ends, data is sent and received only through the new, undeleted IP address.

In addition, in the above-described processing, the handover management unit 73 may check the by-casting flag and control the bi-casting execution unit 74 to operate only when the by-casting is requested or accepted.

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

In the handover of a wireless Internet environment in which data service is provided through a wireless signal, the present invention allows data to be simultaneously transmitted and received to an existing IP address and a new IP address by bicasting, thereby reducing handover delay time. To reduce the possibility of data loss.

1 is a block diagram schematically illustrating a wireless Internet system in which handover is processed.

2 is a flowchart illustrating a conventional SCTP handover method.

3 is a flowchart illustrating a SCTP handover method to which the present invention is applied.

4 is a SCTP message format diagram according to the present invention.

5 is a flowchart illustrating a handover process in a mobile terminal according to the present invention.

6 is a flowchart illustrating a handover process in a counterpart node according to the present invention.

7 is a block diagram showing the configuration of a mobile terminal according to the present invention.

Claims (9)

Checking whether the mobile terminal, which is in data communication with the counterpart node, enters the second IP network through the first IP network; If it is confirmed that the mobile terminal has entered the second IP network, the mobile terminal obtaining a new IP address from the second IP network; Simultaneously transmitting and transmitting the same data by the mobile terminal and the counterpart node simultaneously using the acquired new IP address and the existing IP address used in the first IP network; Checking whether the mobile terminal deviates from the first IP network while performing the bicasting; And If it is determined that the mobile terminal deviates from the first IP network, ending the by-casting between the mobile terminal and the counterpart node and performing data communication using only a new IP address. The method of claim 1, wherein the bicasting step Transmitting, by the mobile terminal, a request message for adding a new IP address indicating whether to perform bicasting to the counterpart node; Receiving a response message including whether to accept the bicasting from the counterpart node; And And if the counterpart node accepts bicasting, performing data communication between the mobile terminal and the counterpart node by bicasting. The method of claim 2, wherein whether to perform the bicasting and whether to accept the bicasting, A bicasting-based SCTP handover method in a wireless Internet environment, which is transmitted through a bicasting flag inserted into a message transmitted between a mobile terminal and a counterpart node. The method of claim 1, wherein terminating the by-casting and performing data communication using only a new IP address comprises: If it is confirmed that the mobile terminal deviates from the first IP network, transmitting a request for deleting the existing IP address to the counterpart node; Receiving, by the mobile terminal, a response message for a request for deleting an existing IP address from a counterpart node; And And, upon receiving the response message, terminating bicasting. 2. A mobility detector detecting whether the mobile terminal enters a new IP network or leaves an existing IP network; An address obtaining unit obtaining a new IP address from the new IP network when the mobility detection unit detects an entry into a new IP network; When the mobility detection unit detects an entry into a new IP network, an additional request message of a new IP address including whether or not to perform bicasting is transmitted to the other node. Handover management unit for transmitting to the counter node; And And a bicasting performer configured to simultaneously transmit the same data by using a new IP address and an existing IP address acquired from the address obtainer. The method of claim 5, wherein the handover management unit And determining whether the partner node has accepted the bicasting, and controlling the bicasting unit to operate when the bicasting is accepted. The method of claim 5, wherein the handover management unit And when the response to the request for deleting the existing IP address is received from the counterpart node, controlling to terminate the by-casting. The method of claim 5, wherein the handover management unit When receiving a new IP address addition request message including whether to perform bicasting from the counterpart node, after adding the new IP address, it is determined whether to accept the bicasting and responds to the counterpart node, and responds to the counterpart node. A mobile terminal, characterized in that for controlling the by-casting unit to be by-cast data to a new IP address. The method of claim 8, wherein the handover management unit The mobile terminal, characterized in that for performing the by-casting, receiving a delete request message of the existing IP address from the counterpart node, deletes the existing IP address and terminates the by-casting.

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