JP2002290442A - Communication device, program, information recording medium, and communication control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication device, a program, an information medium, and a communication device, with which a packet can be received without waiting for a time-out. SOLUTION: The communication device comprises: a communication section 110, which transfers a received packet to a receiving buffer 120, and a determination section 150, which determines whether a desired packet is received within a prescribed time according to identification information of packet stored in the receiving buffer 120. When the determination section 150 determines that the desired packet is not received within the prescribed time, conduction confirmation data including the identification information of the packet are sent to the processing device of a sender of the packet by the communication section 110 for a plurality of times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a communication device, a program, an information storage medium, and a communication control method for performing communication using a TCP / IP protocol via a wireless network.

[0002]

2. Description of the Related Art The TCP / IP protocol is widely used as a communication protocol.

In the TCP / IP protocol, when a packet cannot be transmitted normally within a timeout period, the packet is retransmitted.

[0004] However, since the specifications of the TCP / IP protocol are defined on the premise of a wired network, there are cases where the TCP / IP protocol cannot be used comfortably when used in a wireless network.

That is, in a wireless network, a data error rate is higher than in a wired network, and in the case of mobile communication, the communication state becomes unstable even when a base station is switched.

As described above, when the communication state becomes unstable, the time-out time, that is, the time required for the acknowledgment becomes longer, and comfortable wireless communication cannot be performed.

The present invention has been made in view of the above problems, and has as its object to provide a communication device, a program, an information storage medium, and a communication control method capable of receiving a packet without waiting for a timeout. is there.

[0008]

In order to solve the above problems, a communication device according to the present invention is a communication device that performs communication using a TCP / IP protocol via a wireless network, and performs communication and reception. Communication means for transferring the received packet to a buffer; and determining means for determining whether a desired packet has been received within a predetermined time based on the identification information of the packet stored in the buffer. When determining that the desired packet has not been received within a predetermined time, causing the communication means to transmit the conduction confirmation data including the identification information of the packet to the processing apparatus of the transmission source of the packet a plurality of times. It is characterized by.

A program according to the present invention is a program that can be used by a computer that performs communication using a TCP / IP protocol via a wireless network, and causes a communication unit to communicate and a received packet to be stored in a buffer. A computer for realizing, based on the identification information of the packet stored in the buffer, a determination unit for determining whether or not a desired packet has been received within a predetermined time; When it is determined that the desired packet has not been received within the time, the communication unit transmits the conduction confirmation data including the identification information of the packet to the processing device of the transmission source of the packet a plurality of times. I do.

[0010] An information storage medium according to the present invention is an information storage medium usable by a computer, and includes a program for realizing the above means.

Further, a communication control method according to the present invention is a communication control method for performing communication using a TCP / IP protocol via a wireless network, wherein a received packet is transmitted while a TCP connection is established. Transferring to a buffer; determining whether a desired packet has been received within a predetermined time based on identification information of the packet stored in the buffer; and receiving the desired packet within a predetermined time. If it is determined that the packet does not exist, a step of transmitting the conduction confirmation data including the identification information of the packet to the processing apparatus of the transmission source of the packet a plurality of times;
retransmitting the packet identified by the identification information included in the continuity confirmation data according to a transmission mechanism.

According to the present invention, when it is determined that a desired packet has not been received within a predetermined time, the continuity check data including the identification information of the packet is transmitted a plurality of times to the processing apparatus which has transmitted the packet. By doing, Fa
The packet is immediately transmitted from the processing device by the stRetransmission mechanism.

Therefore, a packet that could not be received can be received without waiting for a timeout.

The identification information includes, for example, T
Sequence number in CP segment ("sequence number"
Also called. ) Can be used.

[0015] Further, the communication device includes means for detecting a traffic state of the wireless network, and the determining means, based on the detected traffic state, when the traffic state is not normal, includes: The continuity check data including the identification information of the packet may be transmitted a plurality of times to the processing device that has transmitted the packet.

Further, the program and the information storage medium cause a computer to implement means for detecting a traffic state of the wireless network (or include a program for causing the computer to implement), and the determination means Based on the traffic state, when the traffic state is not normal, the communication means,
The continuity check data including the identification information of the packet may be transmitted a plurality of times to the processing device that has transmitted the packet.

According to this, by detecting the traffic condition, when the traffic condition is not normal,
Further, packets can be received quickly.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings, taking as an example a case where the present invention is applied to a communication device in a wireless network using a TCP / IP protocol.

FIG. 1 is a diagram showing a configuration of a wireless network according to an example of the present embodiment.

In this network, the communication device 100 and
The server 200 is connected via a wireless transmission path 300.

The communication device 100 requests data from the server 200, and the server 200 transmits packet data to the communication device 100 based on the request.

TCP / IP via wireless transmission path 300
When performing communication using a protocol, the communication state is likely to be unstable compared to communication via a wired transmission path. If the communication state becomes unstable, it is not possible to confirm the response between the communication device 100 and the server 200, and the timeout period becomes longer, and it takes a longer time to receive a packet to be received.

In the present embodiment, the communication device 100 is configured to transmit conduction confirmation data including the sequence number of the packet to the server 200 a plurality of times when a desired packet cannot be received within a predetermined time. I have.

That is, according to the TCP / IP protocol specification, when the conduction confirmation data including the same sequence number is continuously received, the packet having the sequence number is retransmitted. This mechanism is called Fas
This is called a tRetransmission mechanism.

Therefore, by transmitting the continuity check data to the server 200 a plurality of times, the packet is retransmitted before the timeout period elapses, and the packet that could not be received by the communication device 100 can be received in a short time. Becomes possible.

Next, functional blocks of the communication device 100 for realizing this function will be described.

FIG. 2 is a functional block diagram of the communication device 100 according to an example of the present embodiment.

The communication device 100 transmits and receives a packet, transfers the received packet to the reception buffer 120, and stores the packet sequence number stored in the reception buffer 120 and the value indicated by the timer unit 160. And a determination unit 150 that determines whether a desired packet is received within a predetermined time based on the determination.

Further, the communication device 100 includes the reception buffer 1
The communication unit 110 includes a processing unit 130 that performs predetermined data processing based on data in the communication unit 20, and a traffic state detection unit 140 that detects a traffic state based on the communication state of the communication unit 110.

As specific hardware for realizing these units, for example, the communication unit 110 is, for example, a router, and the reception buffer 120 is, for example, RAM.
The processing unit 130, the traffic state detection unit 140, and the determination unit 150 include, for example, a CPU and the like.
As for 60, for example, realization using a system timer or the like can be applied. When each of these units is realized, it may be realized by hardware using a circuit or the like, or may be realized by software using a program.

For example, a program for realizing the functions of the determination unit 150 and the like may be read from the information storage medium 180 to realize the above-described functions.

As the information storage medium 180, for example, C
D-ROM, DVD-ROM, ROM, RAM, HDD
The information can be read by a contact method or a non-contact method.

Further, instead of the information storage medium 180, it is also possible to realize each of the above functions by downloading a program for realizing each of the above functions from a host device or the like via a transmission path. That is, the program for realizing each of the functions described above may be embodied in a carrier wave.

Next, a communication procedure between the communication device 100 and the server 200 will be described.

FIG. 3 is a diagram showing a communication procedure between the communication device 100 and the server 200 according to an example of the present embodiment.

The communication unit 110 has an RMI (Remote
Then, a packet is generated using the method (Method Invocation). Here, the RMI is a mechanism in a JAVA program in which a local JAVA program calls a method of a remote object at the end of a network.
The CP / IP protocol is used. JAVA is a trademark of Sun Microsystems, Inc. of the United States.

The "Sequence" shown in FIG.
“n” means “the sequence number is n” and “Ack
"n" means "the sequence number of the packet desired to be received next time is n", and "PING data" indicates that the packet is the above-described conduction confirmation data.

Hereinafter, the communication procedure will be described.

First, a TCP connection is established between the communication device 100 and the server 200.

Then, the communication unit 110 of the communication device 100 requests the server 200 for 500-byte data. Here, it is assumed that a sequence number is assigned for each byte.

The packet first transmitted from the server 200 has a sequence number of 1 and the contents include the first 100 bytes of the 500-byte data.

The communication unit 110 of the communication device 100 transmits a packet indicating that the sequence number of the packet desired to be received next time is 101 to the server 200.

As described above, when the communication unit 110 transmits a packet indicating that the sequence number of the packet desired to be received next time is 301 to the server 200, the communication state of the wireless section becomes unstable. It is assumed that a packet loss (loss of a packet) occurs.

Based on the value of the timer unit 160, if the data of the packet with the sequence number 301 is not transferred to the reception buffer 120 within the predetermined time, the determination unit 150 requests retransmission of the packet with the sequence number 301. It is determined that it should be.

Then, determination section 150 issues a command to communication section 110 to generate conduction confirmation data having a sequence number of 301.

The communication unit 110 generates conduction confirmation data having a sequence number of 301 based on the command, and transmits the conduction confirmation data to the server 200 twice consecutively.

The server 200 uses the FastRetran
The continuity check data is set to 2
Since the packet has been received consecutively twice, the packet having the sequence number 301 is transmitted to the communication device 100.

Upon confirming that the data of the packet having the sequence number 301 has been transferred to the reception buffer 120, the determination section 150 issues an instruction to the communication section 110 to request transmission of the packet having the next sequence number 401. .
As a result, communication is normally performed again, and the communication device 100
Can receive the requested 500 bytes of data.

As described above, according to the present embodiment, when it is determined that a desired packet has not been received within a predetermined time, the continuity check data including the identification information of the packet is transmitted to the transmission source of the packet. FastRetransmission by sending multiple times to the processing device
The mechanism sends the packet immediately from the processing device.

Therefore, a packet that could not be received can be received without waiting for a timeout.

The application of the present invention is not limited to the above-described embodiment, and various modifications are possible.

For example, in the above-described embodiment, the network is constituted only by the wireless network. However, the present invention is effective for a network including a wired network as long as the communication is performed via the wireless network.

FIG. 4 is a diagram showing the configuration of another network according to an example of the present embodiment.

For example, as shown in FIG.
The present invention is also effective for a network in which a wired network 400 exists in addition to the wireless transmission path 300 between the server 200 and the server 200.

The present invention is also effective when the network is constituted only by a wired network and when a communication device is intermittently connected to the wired network.

When the traffic condition is not normal based on the traffic condition detected by the traffic condition detecting unit 140, the judging unit 150 transmits to the communication unit 110 the conduction confirmation data including the sequence number of the packet. You may make it transmit to 200 several times.

According to this, by detecting the traffic state, if the traffic state is not normal,
Further, packets can be received quickly.

Of course, the continuity check data may be transmitted based on both the data in the reception buffer 120 and the traffic state.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a wireless network according to an example of an embodiment;

FIG. 2 is a functional block diagram of a communication device according to an example of the embodiment.

FIG. 3 is a diagram illustrating a communication procedure between a communication device and a server according to an example of the embodiment.

FIG. 4 is a diagram illustrating a configuration of another network according to an example of the embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 communication device 110 communication unit 120 reception buffer 140 traffic state detection unit 150 determination unit 180 information storage medium

Claims (6)

[Claims] 1. TCP / IP over a wireless network
A communication device for performing communication using a protocol, wherein the communication device performs communication and transfers a received packet to a buffer, and a desired packet is transmitted within a predetermined time based on identification information of the packet stored in the buffer. Determining means for determining whether or not a desired packet has not been received within a predetermined period of time, wherein the determining means determines whether or not the communication means includes identification information of the packet. A communication device for transmitting confirmation data to a processing device of a transmission source of the packet a plurality of times. 2. The wireless communication system according to claim 1, further comprising: means for detecting a traffic state of the wireless network, wherein the determining means, based on the detected traffic state, when the traffic state is not normal, A communication device for transmitting continuity check data including identification information of the packet to a processing device that has transmitted the packet a plurality of times. 3. TCP / IP over a wireless network
A program that can be used by a computer that performs communication using a protocol, wherein the program communicates with a communication unit and transfers a received packet to a buffer; and Determining means for determining whether or not a desired packet has been received within, and causing the computer to implement the following. If the determining means determines that the desired packet has not been received within a predetermined time, the communication means A program for transmitting conduction confirmation data including identification information of the packet to a processing device that has transmitted the packet a plurality of times. 4. The wireless communication system according to claim 3, wherein the computer implements means for detecting a traffic state of the wireless network, and wherein the determining means performs the communication when the traffic state is not normal based on the detected traffic state. A program causing the means to transmit the conduction confirmation data including the identification information of the packet to the processing device of the transmission source of the packet a plurality of times. 5. An information storage medium usable by a computer, wherein the information storage medium includes the program according to claim 3. 6. TCP / IP over a wireless network
A communication control method for performing communication using a protocol, comprising: a step of transferring a received packet to a buffer while a TCP connection is established; and a method of transmitting a received packet to a buffer for a predetermined time based on identification information of the packet stored in the buffer. Determining whether a desired packet has been received within a predetermined time period; and, if determining that the desired packet has not been received within a predetermined time period, transmitting continuity check data including identification information of the packet to a source of the packet. Transmitting to the processing device a plurality of times; and in the processing device of the transmission source, FastRetran
retransmitting the packet identified by the identification information included in the continuity check data in accordance with the transmission mechanism.