KR100812822B1 - Wireless Data Communication Method Based on Destination Status in Wireless Network System - Google Patents

Abstract

The present invention relates to a wireless data communication method based on a destination state in a wireless network system. The wireless data communication of the present invention is performed in a wireless network system including a transmitting terminal, a router, and a receiving terminal, and the router is connected to another router or a destination. If the status of the corresponding receiving terminal is checked, and as a result, packet data cannot be transmitted to the receiving terminal, an error message is generated and transmitted to the transmitting terminal.

Wireless Network System, Packet Data, Router, Sending Terminal

Description

WIRELESS DATA COMMUNICATION METHOD FOR BEING ON THE BASIS OF STATE OF DESTINATION

1 is a diagram illustrating an example of data communication between a transmitting end 10 and a receiving end 20 according to a transmission control protocol (TCP) of a conventional communication system.

2 is a block diagram showing the configuration of a wireless network system to which the present invention can be applied.

3 shows a packet data structure generated in the transmitting terminal 10 according to the present invention.

4 illustrates a wireless data communication method based on a destination state in a wireless network system according to the present invention.

The present invention relates to a method of wireless data communication based on a destination state in a wireless network system.

As a protocol for transmitting data over the Internet, Request For Comments (RFC) 793 issued by the Internet Engineering Task Force (IETF), an Internet standardization organization, defines the Transmission Control Protocol (hereinafter referred to as TCP). Doing. Transmission control protocol (TCP) is used to transmit data transmitted and received between nodes connected to the Internet in the form of packets. Such a transmission control protocol (TCP) operates as a transport layer protocol above the Internet protocol (hereinafter referred to as IP) of the network layer, and therefore is usually referred to as TCP / IP. do.

1 is a diagram illustrating an example of data communication between a transmitting end 10 and a receiving end 20 according to a transmission control protocol (TCP) of a conventional communication system.

Referring to the drawings, in order to increase the reliability of data transmission and reception, TCP uses a scheme in which the receiving end 20 transmits an ACK packet to confirm data reception with respect to the transmitting end 10. Here, the transmitting end 10, for example, during TCP Setup or TCP, sends an ACK packet indicating that the TCP segmant is normally received from the server after receiving the TCP segmant to the destination server until the ACK packet of the previously sent TCP segment comes. After waiting for Retransmission_timeout_val (the limit of timers to retransmit) depending on the round trip time (RTT) and the number of retransmissions, if the ACK packet does not come in as long as Retransmission_timeout_val, the maximum retransmission count (TCP_MAX_BACKOFF) + 1 Unless caught, retransmission will be performed.

However, if the method is applied as it is, it is very inefficient in the following cases. For example, the transmitting end 10 may not be able to reach the destination network or host (relative server) due to the absence of a destination network or host (relative server) or a hardware failure of the destination network or host (relative server). In this case, unnecessary retransmissions must be made as many times as TCP_MAX_BACKOFF. In addition, if a TCP SEGment is sent to a destination that does not exist for TCP Setup for a time period of Retransmission_timeout_val, which is determined by the round trip time (RTT) and the number of retransmissions for each retransmission, the destination is sent from the destination. You have to wait approximately 190000 ms (3 minutes) for the ACK packet to come. Furthermore, there is an inefficient aspect that the terminal should keep TCP and TCP sockets for the delayed time while waiting ACK packet that will not come even if it does not wait due to the absence or failure of the destination. .

The present invention has been proposed in the above background, and an object of the present invention is to enable a user who uses wireless data communication in a wireless network system to determine whether or not the current wireless data communication can be performed smoothly. It is to provide a technology that can be confirmed with.

A further object of the present invention is to wait for an ACK packet not to be caused by a router or a receiving terminal which is not present or failed during a wireless data communication TCP setup process or communication at a transmitting terminal, and does not unnecessarily perform a packet data retransmission process. For example, by performing the TCP and TCP Socket Close processing routines of the terminal, it provides a technique for quickly cleaning terminal resources and quickly delivering a message such as a network server error to a user.

Wireless data communication according to an aspect of the present invention for achieving the above object is made in a wireless network system including a transmitting terminal, a router and a receiving terminal, the router checks the state of the receiving terminal corresponding to another router or destination As a result, when the packet data cannot be transmitted to the corresponding receiving terminal, an error message is generated and transmitted to the transmitting terminal which sent the packet data.

According to this aspect, the user using the wireless data communication through the transmitting terminal can check in real time whether the current wireless data communication can be performed smoothly and the communication is performed smoothly.

The wireless data communication method based on a destination state in a wireless network system according to an additional aspect of the present invention further includes the step of stopping, by the transmitting terminal, packet data transmission when an error message is input.

According to this aspect, the transmitting terminal solves the problem of unnecessarily performing packet data retransmission process while waiting for an ACK message which will not come due to the router or the receiving terminal which is not present or failed during the wireless data communication setup process or communication. can do. Furthermore, when an error message is input, the transmitting terminal can quickly deliver a message such as network server error to the user and quick cleanup of terminal resources by performing a TCP and TCP socket close processing routine of the terminal.

According to another aspect of the present invention, a wireless data communication method based on a destination state in a wireless network system generates an error message to a transmitting terminal that generates an error message when the receiving terminal cannot process packet data received from a router. The method further includes the step of transmitting.

According to this aspect, the user using the wireless data communication through the transmitting terminal can determine in real time whether the cause of the current wireless data communication is not a router, a network problem or a problem of the receiving terminal.

In a wireless network system according to an additional aspect of the present invention, a wireless data communication method based on a destination state is first transmitted in a corresponding packet data header when a packet data to be transmitted by a transmitting terminal is packet data first transmitted without a retransmission process yet. Set a field value indicating that the packet data is to be transmitted, and check the field value indicating that the packet data is initially transmitted without going through the retransmission process in the received packet data header. Check the status of the receiving terminal corresponding to another router or destination based on the IP address information.

According to this aspect, the transmitting terminal stops the first retransmission timer for the corresponding message, which was started when the message was first sent without retransmission, when an error message is input and no longer performs the retransmission mechanism. In addition, it closes the TCP protocol and the TCP socket maintained by the sending terminal, and can quickly clean up terminal resources and deliver a message such as a network server error to the user.

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 can easily understand and reproduce the present invention.

2 is a block diagram showing the configuration of a wireless network system to which the present invention can be applied.

As shown, the wireless network system forms a direct wireless path with the transmitting terminal 10, and the base station (BS) 12, which serves to change the signal format to suit the wireless link and the wired link, Exchanging data packet information between the base station controller (BSC) 14 and the base station controller (BSC) 14 and the PDSN 18 that perform information collection, monitoring and management related to the operation of the base station (BS) 12. A packet data service node (PDSN) 18 interworking with the BSC 14 via the packet control device (PCF) 16 and the PCF 16 to control the overall high speed data communication between the mobile communication network and the Internet network; A home agent (HA) that interoperates with the PDSN (18) to perform mobile IP authentication for packet services, and a wireless data service authentication server and a receiving terminal (20) for subscriber authentication, authorization verification, and billing for wireless data services. With a router for forwarding packet data to It includes a communication network 30 including a plurality of networks. Through such a wireless network system, the transmitting terminal 10 exchanges packet data with a receiving terminal 20, for example, a computer device, connected to the communication network 30.

Here, the transmitting terminal 10 may be a laptop connected to a cellular telephone or a personal communications service (PCS) telephone, a personal digital assistant (PDA) telephone or an international mobile telecommunication (IMT) -2000 terminal capable of internet communication. The receiving terminal 20 may be a web server, a file transfer protocol (FTP) server, or the like. The transmitting terminal 10 transmits data segments generated by dividing files to be transmitted to the receiving terminal. Preferably, the transmitting terminal 10 and the receiving terminal 20 are implemented to communicate using a Transmission Control Protocol (TCP) based on the Internet Protocol (IP).

3 shows a packet data structure generated in the transmitting terminal 10 according to the present invention.

The protocol of each layer of TCP / IP of the transmitting terminal 10 sends a message with a header to send. The process of attaching a header to the lower layer is called data encapsulation. 3 shows a TCP header, a source IP address, a destination IP address, a sequence number used to prevent the data transmission order and arrival order from being reversed, and the receiving side. Acknowledgment number, offset header length for received packets, reserved reserved for future use by TCP for future expansion, and flags used for packet segmentation ( Flage), a window that shows the size of data that can be transferred at one time on a TCP connection, a checksum that checks that the TCP header and data are working properly, and any data to be sent urgently. It includes options area that specifies various options such as the urgent pointer used, security, and the method of delivering packets.

4 illustrates a wireless data communication method based on a destination state in a wireless network system according to the present invention.

As shown, the wireless network system according to the present invention can be largely implemented by including a transmitting end 10 including a transmitting terminal, a router 31 and a receiving end 20 including a receiving terminal. The transmitting terminal according to the present invention does not unnecessarily perform a packet data retransmission process, for example, immediately waiting for an ACK packet not coming due to a router 31 or a receiving terminal that does not exist or has failed during a TCP setup process or communication. By executing TCP and TCP Socket Close processing routines of the terminal, it is implemented to quickly clean up terminal resources and deliver messages such as network server errors to the user.

The transmitting terminal generates packet data during TCP setup or communication (S401). When the sending terminal sends a TCP segmant during TCP setup or communication, if the segment is the first transmission without retransmission, the round trip time (RTT: RoundTripTime) and retransmission, which is the measurement time until the ACK packet of the previously sent TCP segmant comes, The first retransmission timer is run with Retransmission_timeout_val, which is determined by the number of times. According to an embodiment, when the packet data to be transmitted by the transmitting terminal is packet data first transmitted without undergoing a retransmission process yet, the transmitting terminal may set a field value indicating that the packet data is initially transmitted in the packet data header. In one example, the transmitting terminal may set this field value in a reserved area in the TCP header.

The transmitting terminal transmits the packet data to the wireless network (S402). The router 31 receives the packet data and checks the state of a receiving terminal corresponding to another router or destination based on the destination IP address information included in the packet data (S403). In other words, the packet data is transmitted to the counterpart server having the destination IP through routers included in several specific networks. For example, router A in network A has a routing table necessary to send packet data to a partner server having a destination IP. The router checks whether the router belonging to the same B network is available by using the status information of the routing table and the network address of the destination IP address (S404). On the other hand, if the network address portion of the destination IP address included in the received packet data is the same as the address of the network A, the router A in the network A uses or does not exist if a host (relative server) having the destination IP address actually exists. Whether it is possible will be checked through the state information in the routing table.

In one embodiment, the router checks a field value indicating that the packet data is initially transmitted without going through a retransmission process in the received packet data header, and then the other router based on the destination IP address information included in the checked packet data. Or it may be implemented to check the state of the receiving terminal corresponding to the destination.

Thereafter, when the router 31 is unable to transmit packet data to a receiving terminal corresponding to another router or a destination, the router 31 generates an error message and transmits the packet data to the transmitting terminal (S405 and S406). At this time, the router 31 uses the source IP address in the TCP header of the TCP segmant sent by the transmitting terminal to transmit an error message to the terminal.

Subsequently, when the transmitting terminal inputs an error message indicating that the destination network or host does not exist or is unavailable, the first retransmission timer for the TCP segmant started when the TCP segmant was sent, Timer Cancel. And do not perform the retransmission mechanism anymore (S407). In addition, the sending terminal closes the TCP protocol and the TCP socket, which have been kept, and displays a message such as a network server error to the user and quick cleaning of the terminal resources.

On the other hand, if the router 31 can transmit the packet data to the router included in the other network or the corresponding receiving terminal in step S404, and transmits the packet data input from the transmitting terminal to the receiving terminal 20 (S408). Thereafter, the receiving terminal checks whether the packet data received from the router 31 can be processed (S411). For example, the receiving terminal may not be able to process the TCP segmant due to a problem of the TCP or more layer. If the receiving terminal is unable to process, it generates an error message and transmits the packet data to the transmitting terminal (S412, S413). At this time, the receiving terminal uses the source IP address in the TCP header of the TCP segmant sent by the transmitting terminal to use the destination IP address when transmitting an error message to the terminal.

At this time, when the transmitting terminal inputs an error message indicating that the destination network or host does not exist or is unavailable, the first retransmission timer for the corresponding TCP segmant started when the TCP segmant was sent, Timer Cancel. And do not perform the retransmission mechanism anymore (S407). In addition, the sending terminal closes the TCP protocol and the TCP socket, which have been kept, and displays a message such as a network server error to the user and quick cleaning of the terminal resources.

As described above, according to the present invention, the transmitting terminal waits for an ACK message that will not come due to the router or the receiving terminal which is not present or failed during the wireless data communication setup process or communication, and is caused by unnecessarily performing the message retransmission process. It can solve the problem of communication delay for hundreds of seconds (about 190000 ms).

Furthermore, according to the present invention, when an error message is input, the transmitting terminal has a useful effect of, for example, performing a TCP and TCP Socket Close processing routine of the terminal to quickly clean up terminal resources and quickly deliver a message such as a network server error to the user.

According to this aspect, the user using the wireless data communication through the transmitting terminal has a useful effect that can determine in real time whether the cause of the current wireless data communication is not a router, a network problem or the receiving terminal.

Although the present invention has been described with reference to the accompanying drawings, it will be apparent to those skilled in the art that many various obvious modifications are possible without departing from the scope of the invention from this description. Therefore, it should be interpreted by the claims described to include many such variations.

Claims (5)

A wireless data communication method based on a destination state in a wireless network system including a transmitting terminal, a router, and a receiving terminal, Generating and transmitting packet data by the transmitting terminal; Receiving, by the router, the packet data and checking a state of a receiving terminal corresponding to another router or a destination based on destination IP address information included in the packet data; Generating an error message and transmitting the packet data to the transmitting terminal when the router cannot transmit packet data to a receiving terminal corresponding to another router or a destination as a result of the checking; Wireless data communication method based on the destination state in a wireless network system comprising a. The method of claim 1, wherein the wireless data communication method based on a destination state in the wireless network system includes: Stopping, by the transmitting terminal, packet data transmission when the error message is input; The wireless data communication method based on the destination state in a wireless network system, further comprising. 3. The method of claim 1 or 2, wherein the method of wireless data communication in the wireless network system is based on a destination state: Transmitting packet data to the receiving terminal when the router is able to transmit the packet data to the receiving terminal corresponding to the destination as a result of the checking; Receiving, by the receiving terminal, the transmitted packet data; And And generating an error message and transmitting the packet data to the transmitting terminal when the receiving terminal is unable to process the input packet data. Communication method. The method of claim 1 or 2, wherein the transmitting terminal generates and transmits packet data: When the transmitting terminal currently transmits the packet data to be transmitted for the first time without any retransmission process, it sets and transmits a field value indicating that the packet data is first transmitted in the corresponding packet data header. The router receives the packet data and checks a state of a receiving terminal corresponding to another router or a destination based on the destination IP address information included in the packet data. The router checks a field value indicating that the packet data is initially transmitted without retransmission in the received packet data header, and then the router determines another router or destination based on the destination IP address information included in the checked packet data. And confirming a state of a receiving terminal to be received, the wireless data communication method based on a destination state in a wireless network system. The method of claim 4, wherein The field value indicating that the packet data is first transmitted in the packet data header, And a transmitting terminal sets a reserved area in a packet data header.

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