JP2004241872A - Information communication method and repeating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To retransmit information on the limited part of a path, even if the information is lost at the middle part of the path between two information communication terminals for transmitting/receiving the information. <P>SOLUTION: In the repeating device 201, a communication data receiving section 211 receives reception data or reception response and fetches a UDP datagram from the reception data, a communication data storing/fetching section 230 stores the datagram in a data storing section 202, a connection setting section 241 establishes a TCP connection to a transmission destination, a communication data buffer 243 generates and holds a TCP segment in which the data of communication information is used as the UDP datagram from the UDP datagram fetched from the data storing unit and a TCP header and an IP header generated in a communication header generating unit 242, and a communication data transmitting section 250 transmits the TCP segment to the next repeating device. The reception response is detected by a reception response determining section 220, the data in the data storing section are deleted if the reception response is a response within a time set in a timer setting section 212, and the TCP segment is retransmitted if it is out of the set time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an information communication method and a relay device between information communication terminals, and more particularly to an information communication method and a relay device that are effective in a network environment in which information loss occurs on an intermediate route between information communication terminals.
[0002]
[Prior art]
2. Description of the Related Art With the spread of the Internet, information has been frequently transmitted and received between information communication terminals such as PCs (personal computers) and between information communication terminals and various server systems in companies and homes.
In many cases, transmission and reception of such information is performed by using a protocol called TCP (Transmission Control Protocol: RFC 793) or UDP (User Datagram Protocol: RFC 768).
Prior to transmission and reception of information, TCP establishes a logical line called a connection between two information communication terminals that perform communication, and controls order of information, retransmission, This is a protocol having a function of performing flow control and congestion control, and is a protocol having an acknowledgment.
UDP is a protocol used to reduce processing required by limiting functions and to increase processing speed, and is a protocol without acknowledgment.
Since UDP is a protocol that does not have the above functions in TCP, in order to improve the reliability of information to be transmitted and received, functions required by a higher-level user application program using UDP, for example, It is necessary to realize functions such as transmission individually.
[0003]
[Problems to be solved by the invention]
According to such a conventional technique, when information is lost on an intermediate route between two information communication terminals that transmit and receive information, for example, due to a failure of a relay device, the information is transmitted again from the information communication terminal that transmitted the information. Therefore, the same information flows repeatedly on the route to the failed relay device, and there is a problem that the amount of communication of the information flowing on the entire communication route increases.
Also, if information is lost on an intermediate route, the time until the information is transmitted again from the information communication terminal that transmitted the information depends on the information communication terminal that transmits the information. In an information communication terminal in which the time until retransmission is set, there is a problem that information is not retransmitted for a long time.
An object of the present invention is to retransmit information only on a part of the route even if the information is lost, on the route between two information communication terminals that transmit and receive information.
Another object of the present invention is to make it possible to retransmit information more quickly than in the past when information is lost on an intermediate route between two information communication terminals that transmit and receive information.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, information is transmitted and received between information transmitting and receiving apparatuses using a protocol without acknowledgment (hereinafter, referred to as a first protocol), and communication information from a transmitting side information transmitting and receiving apparatus is received. The relay device on the communication path converts a protocol data unit (hereinafter, referred to as PDU) of the first protocol in the received communication information into a service data unit of a protocol (hereinafter, referred to as a second protocol) having an acknowledgment. (Hereinafter, referred to as SDU), and performs communication using the second protocol with the relay device after the connection is established by the second protocol as communication information having PDU of the second protocol, and The communication device having the PDU of the second protocol when there is no reception response from the relay device of the transmission destination of the communication information The retransmission is performed, and the relay device at the transmission destination of the communication information connected to the reception-side information transmission / reception device extracts the PDU of the first protocol from the received communication information having the PDU of the second protocol, and Is transmitted to the receiving side information transmitting / receiving device via the communication path.
Also, the present invention provides a method for transmitting and receiving information between information transmitting and receiving apparatuses using a second protocol, wherein a relay apparatus on a communication path that receives communication information from a transmitting-side information transmitting and receiving apparatus transmits a second information in the received communication information. PDU of the second protocol as the SDU of the PDU of the new second protocol, and the relay device and the second protocol after the connection is newly established with the second protocol as communication information having the PDU of the new second protocol The communication relay device performs communication using the communication device, and the relay device that transmits the communication information retransmits the communication information having the PDU of the second protocol when there is no reception response from the relay device that is the transmission destination of the communication information. The relay device at the transmission destination of the communication information connected to the information transmission / reception device transmits the communication information having the received PDU of the second protocol to the transmission-side information transmission / reception device. Removed PDU of a second protocol signal, the PDU of the second protocol via the communication path to transmit toward the receiving-side information transceiver.
[0005]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
Note that the name of the communication information in the protocol without the acknowledgment (referred to as the first protocol) is referred to as "protocol data unit (PDU)", and particularly the name of the data portion is referred to as "service data unit (SDU)". Call it.
That is, the PDU of the first protocol includes the header of the first protocol and the SDU of the first protocol.
In the following, description will be made using UDP as a protocol without an acknowledgment.
Also, the communication information in the protocol having the acknowledgment (referred to as the second protocol) is called "protocol data unit (PDU)", and the data part is called "service data unit (SDU)". Call it.
That is, the PDU of the second protocol includes a header of the second protocol and an SDU of the second protocol.
In the following, a description will be given using TCP as a protocol with an acknowledgment.
[0006]
FIG. 1 shows a connection relationship between a communication path and a relay device to which the present invention is applied.
FIG. 1 shows a path for transmitting information from an information transmitting / receiving apparatus, for example, a personal computer A (101) to an information transmitting / receiving apparatus B (102) via relay apparatuses (103 to 111). A description will be given of a means for automatically retransmitting information even when information is lost in the section by using a UDP datagram as data of a TCP segment in a part of a communication path.
The information transmitted from the information transmitting / receiving apparatus A (101) is received by the relay apparatus T1 (103), and the relay apparatus T1 (103) transmits the information to the information transmitting / receiving apparatus B (102), which is the destination of the received information. By transmitting information to an appropriate relay device, for example, the relay device T4 (106) in the middle of the process, and repeating the selection of an appropriate relay device and transmission to the selected relay device, finally, the information transmitting / receiving device The information is transmitted to the relay device connected to B, for example, the relay device Tn (111).
The relay device Tn (111) transmits the received information to the information transmitting / receiving device B (102).
When information is transmitted from the information transmitting / receiving device A (101) using UDP, if the information is lost in the middle of the route, for example, if the information is not transmitted due to the failure of the relay device T5 (107), the lost information is automatically transmitted. Since there is no means for transmitting the information again, the user application program operating on the information transmitting / receiving apparatus A (101) needs to perform processing such as transmitting the information again if there is no response within a predetermined time.
[0007]
According to the present invention, when a UDP datagram is transmitted from an information transmitting / receiving device, a UDP datagram to be transmitted is used as TCP segment data between relay devices located in the middle of a communication path, and communication using TCP is performed. From the TCP segment received by the relay device on the receiving side of the TCP connection, a UDP datagram serving as the data is extracted.
In the case of FIG. 1, when transmitting a UDP datagram from the information transmitting / receiving apparatus A (101) to the information transmitting / receiving apparatus B (102), the relay apparatus T1 (103) and the relay apparatus Tn (111) in the middle of the communication path. Then, the UDP datagram to be transmitted is set as data of the TCP segment, communication using TCP is performed, and the relay device Tn (111) extracts the UDP datagram as the data from the received TCP segment. Then, the extracted UDP datagram is transmitted to the information transmitting / receiving apparatus B (102).
Accordingly, even if information is lost while the TCP segment transmitted from the relay device T1 (103) is transferred to the relay device Tn (111), the relay device that transmitted the lost information (for example, the relay device T1 (103) )) Determines that there is no reception response from the relay device (for example, the relay device Tn (111)) to which the information has been transmitted, and automatically retransmits the information. Therefore, the information transmitting / receiving apparatus A (101) does not need to retransmit information even if information transmitted to the information transmitting / receiving apparatus B (102) is lost in the middle.
[0008]
The relay device Tn (111) transmits a reception response to the relay device T1 (103) when the TCP segment transmitted from the relay device T1 (103) and using the UDP datagram as the data arrives, and transmits the TCP segment. Then, the UDP datagram which is the data of (1) is taken out and transmitted to the information transmitting / receiving apparatus B (102) which is the actual destination.
In FIG. 1, the relay device and the information transmitting / receiving devices A and B are separately provided. However, the relay device may exist in the information transmitting / receiving device A or B.
[0009]
FIG. 2 is a block diagram illustrating a configuration of the relay device.
The relay device 201 includes an event monitoring unit 210, a reception response determination unit 220, a communication data storage / retrieval unit 230, a data storage unit 202, a communication data processing unit 240, and a communication data transmission unit 250.
The event monitoring unit 210 monitors an event, and includes a communication data receiving unit 211 and a timer setting unit 212.
Here, the event is, for example, the arrival and reception of communication data to the relay device 201, or the passage of a predetermined time set as a timer.
The communication data receiving unit 211 receives communication data that has reached the relay device 201, and the received communication data is passed to the reception response determination unit 220.
The timer setting unit 212 sets a time when communication data is transmitted from the relay device 201, and outputs a timeout signal when the set time has elapsed.
If a reception response does not arrive even after a set time has elapsed for the communication data transmitted from the relay device 201, the communication data is transmitted again.
[0010]
If the communication data passed from the communication data receiving unit 211 is a reception response to the communication data previously transmitted from the relay device 201, the reception response determination unit 220 The communication data is instructed to be deleted, and if the reception of the communication data is not a reception response, the reception data is stored in the communication data storage / retrieval unit 230 as the storage data in the data storage unit 202. After the instruction, the communication data processing unit 240 is instructed to transmit the communication data.
[0011]
The communication data storage / retrieval unit 230 receives the communication data when the determination by the reception response determination unit 220 is the reception of the communication data. The received data is stored in the storage unit 202, and when the determination of the reception response determination unit 220 is a reception response, and when an instruction to delete communication data is received from the reception response determination unit 220, the communication data is deleted according to the instruction. Further, when data is transmitted to the next relay device or information transmitting / receiving device, the stored data is extracted from the data storage unit 202.
[0012]
The communication data processing unit 240 includes a connection setting unit 241, a communication header generation unit 242, and a communication data buffer unit 243.
The connection setting unit 241 establishes a TCP connection for the received communication data with an appropriate relay device on an intermediate route to the destination of the communication data. When the device to which the connection is to be established is the information transmitting / receiving device that is the original destination of the UDP datagram, the connection setting unit 241 removes the TCP header / IP header from the received TCP segment. The datagram is taken out from the data storage unit and transmitted to the information transmitting / receiving device that is the original destination by the communication data transmitting unit 250.
Here, it is determined that the establishment of the TCP connection is performed only when appropriate information is added to the communication data, or that the establishment of the TCP connection is performed only when appropriate information is not added. The determination may be performed based on the determination that the communication is performed only for communication data that satisfies conditions such as an appropriate destination set by an instruction of the administrator.
[0013]
The communication header generation unit 242 generates a TCP header / IP header in the TCP connection established by the connection establishment unit 241.
The communication data buffer unit 243 generates a TCP segment from the TCP header / IP header generated by the communication header generation unit 242 and the UDP datagram which is communication data extracted from the communication data storage / extraction unit 230, and The data is temporarily stored until the data transmission unit 250 actually transmits the data. If the TCP header / IP header is not generated by the communication header generation unit 242, the communication header is extracted from the communication data storage / extraction unit 230. The data is temporarily held until the communication data transmitting unit 250 actually transmits a UDP datagram as communication data.
The communication data transmission unit 250 receives the TCP segment or the UDP datagram held in the communication data buffer unit 243, and transmits the TCP segment or the UDP datagram to the next relay device or the information transmission / reception device that is the original destination.
[0014]
FIG. 3 is a flowchart of the transmission process of the relay device, including the operation of the communication data processing unit 240, performed when the transmission of the communication data is instructed, in the case where the communication data is transmitted to the next relay device. It is a flow.
First, the communication data processing unit 240 instructs the communication data storage / retrieval unit 230 to retrieve stored data, and retrieves communication data to be transmitted (storage data acquisition 301).
Next, the connection setting unit 241 determines whether or not a connection has already been established with an appropriate relay device on an intermediate route based on information such as a destination included in the extracted communication data. If not, a TCP connection using the extracted communication data as the data portion of the TCP segment is established with an appropriate relay device on the intermediate route, and the correspondence between the extracted communication data and the TCP connection is set in a connection establishment table. (Send destination address acquisition 302).
[0015]
An appropriate relay device for establishing a TCP connection is automatically selected for each extracted communication data, but can be arbitrarily specified by an administrator of the relay device.
Next, the communication header generation unit 242 generates a TCP header / IP header based on the TCP connection established by the connection setting unit 241. If a TCP connection has already been established, a TCP header / IP header is generated based on the TCP connection. A header / IP header is generated, and a TCP segment is generated in the communication data buffer unit 243 by combining the generated TCP header / IP header and the communication data extracted from the communication data storage / extraction unit 230 (transmission data processing 303). ).
[0016]
Next, in the communication data transmitting unit 250, the TCP segment generated by the communication data buffer unit 243 is taken out, the destination relay device of the TCP connection established by the connection setting unit 241 is selected, and the selected relay device is sent to the selected relay device. Then, the extracted TCP segment is transmitted (processed data transmission 304).
Next, in the timer setting unit 212, a time until transmission is performed again when a reception response to the transmitted communication data does not arrive (timer setting 305).
This time may be set to a fixed time at all times, but it may be set to a time that is appropriately increased or decreased each time retransmission is performed, or the time from when communication data is transmitted until the reception response arrives. A time that takes into account (response time) may be set.
The timer setting 305 may be performed prior to the processing of the processed data transmission 304.
[0017]
After that, it waits until the event is notified from the event monitoring unit 210, and when the communication data receiving unit 211 notifies of the event that the communication data is received, it is a reception response to the communication data transmitted by the response reception determining unit 220. It is determined whether or not the response is a reception response to the communication data. If the response is a reception response to the communication data, the connection setting unit 241 deletes the connection information for the communication data from the connection establishment table, and the communication data storage and retrieval unit 230 Instructs the data storage unit 202 to delete the communication data (stored data deletion 307).
When an event indicating that a certain period of time has elapsed since the transmission of the communication data is notified from the timer setting unit 212 instead of the event notification from the communication data receiving unit 211, the stored data acquisition 301 is performed again on the communication data. The transmission process is performed (timeout 308).
[0018]
In the embodiment described above, information transmission / reception is performed between information transmitting / receiving apparatuses using UDP. However, transmission / reception of TCP segments (IP header / TCP header / TCP data) between information transmitting / receiving apparatuses using TCP is described. Is performed, the TCP segment to be transferred between the relay device T1 (103) and the relay device Tn (111) in the middle of the communication path is set as new TCP segment data. The communication using TCP is performed, and the relay device Tn (111) immediately before the information transmitting / receiving device B (102) on the receiving side extracts the TCP segment as the data from the received TCP segment, and extracts the extracted TCP segment. You may make it transmit to the information transmission / reception apparatus B (102).
In this case, when the information is lost on the intermediate route, the information is retransmitted from the relay device in the middle of the communication route without retransmitting the information from the information transmitting / receiving device A (101) on the transmitting side.
[0019]
FIG. 4 shows a mechanism for generating a TCP segment transmitted by the communication data transmitting unit 250 in the communication data buffer unit 243 of FIG.
First, the stored data 431 extracted by instructing the communication data storage / extraction unit 403 is stored as communication data 411 in the communication data buffer unit 401.
The stored data 431 and 432 are stored in the form of communication data received by the relay device, for example, in the case of using a UDP protocol, in the form of an IP header / UDP header / UDP data. Is stored in the form of an IP header, a TCP header, and TCP data.
Next, in the connection setting unit 402, a corresponding TCP header / IP header 421 is generated based on the extracted stored data 411, and a TCP header / IP header 421 is provided before the communication data 411 stored in the communication data buffer unit 401. It is placed as an IP header 412 and a TCP segment is generated.
[0020]
【The invention's effect】
According to the present invention, even when information is lost on an intermediate route between two information communication terminals that transmit and receive information, information is retransmitted only to a part of the route, so that information flowing on a network is transmitted. Communication volume can be reduced.
[Brief description of the drawings]
FIG. 1 shows a connection relationship between a communication path and a relay device to which the present invention is applied.
FIG. 2 is a block diagram illustrating a configuration of a relay device.
FIG. 3 is a diagram showing a flow of a transmission process of a relay device, including an operation of a communication data processing unit 240, performed when an instruction to transmit communication data is given.
FIG. 4 shows a mechanism for generating a TCP segment transmitted by a communication data transmission unit 250 in a communication data buffer 243.
[Explanation of symbols]
101, 102 information transmission / reception devices 103 to 111 relay device 201 relay device 202 data storage unit 210 event monitoring unit 211 communication data reception unit 212 timer setting unit 220 reception response determination unit 230 communication data storage / retrieval unit 240 communication data processing unit 241 connection Setting unit 242 Communication header generation unit 243 Communication data buffer unit 250 Communication data transmission unit

Claims (10)

An information communication method for transmitting and receiving information between information transmitting and receiving devices via a relay device on a communication path,
Information is transmitted and received between the information transmitting and receiving devices using a protocol without acknowledgment (hereinafter, referred to as a first protocol), and the relay device on the communication path that receives the communication information from the transmitting information transmitting and receiving device receives the received communication information. A protocol data unit (hereinafter, referred to as PDU) of a first protocol is a service data unit (hereinafter, referred to as SDU) of a protocol (hereinafter, referred to as a second protocol) having an acknowledgment, and Communication is performed using the second protocol with the relay device after the connection is established by the second protocol as communication information having the PDU of the protocol, and the relay device as the transmission source of the communication information transmits the communication information. When there is no reception response from the relay device, the communication information having the PDU of the second protocol is retransmitted. The relay device of the transmission destination of the communication information connected in step 1 extracts the PDU of the first protocol from the received communication information having the PDU of the second protocol, and transfers the PDU of the first protocol to the communication path. And transmitting the information to the receiving-side information transmitting and receiving apparatus via the receiving side. The information communication method according to claim 1,
The relay device extracts a PDU of the first protocol from the received communication information, stores the PDU, and
The stored PDU of the first protocol is read, a PDU of the second protocol is generated by using the PDU of the first protocol as an SDU, and communication information having the PDU of the second protocol is transmitted on a communication path. And determine whether a reception response has arrived within a predetermined time,
As a result of the determination, if there is no reception response, the PDU of the second protocol is generated and the communication information is retransmitted. If there is a reception response, the stored PDU of the first protocol is deleted. Information communication method. The information communication method according to claim 1,
An information communication method, wherein the relay device performs communication according to a first protocol when predetermined specific information is not set in the received communication information. The information communication method according to claim 1,
The information communication method, wherein the relay device performs communication according to a first protocol when predetermined specific information is set in the received communication information. An information communication method for transmitting and receiving information between information transmitting and receiving devices via a relay device on a communication path,
Information is transmitted and received between the information transmitting and receiving devices using the second protocol, and the relay device on the communication path that has received the communication information from the transmitting information transmitting and receiving device renews the PDU of the second protocol in the received communication information. A second SDU of the PDU of the second protocol is used as the communication information having the PDU of the new second protocol, and the communication is performed using the second protocol with the relay device after the connection is newly established with the second protocol. When there is no response from the relay device at the transmission destination of the communication information, the relay device at the transmission source of the communication information retransmits the communication information having the PDU of the second protocol and connects to the reception-side information transmission and reception device. The relay device that is the transmission destination of the received communication information transmits the second protocol transmitted by the transmission-side information transmitting / receiving device from the received communication information having the PDU of the second protocol. Removed PDU of Tokoru, information communication method of the PDU of the second protocol via the communication path and transmitting toward the receiving-side information transceiver. The information communication method according to claim 5,
The relay device extracts a PDU of the second protocol from the received communication information, stores the PDU,
The stored PDU of the second protocol is read, a PDU of the second protocol is generated by using the PDU of the second protocol as an SDU, and communication information having the PDU of the second protocol is transmitted on a communication path. And determine whether a reception response has arrived within a predetermined time,
As a result of the determination, if there is no reception response, the PDU of the second protocol is generated and the communication information is retransmitted. If there is a reception response, the stored PDU of the second protocol is deleted. Information communication method. The information communication method according to claim 5,
The relay device, when the predetermined specific information is not set in the received communication information, converts the PDU of the second protocol in the received communication information into the SDU of the PDU of the new second protocol. An information communication method comprising performing communication according to a second protocol without performing communication. The information communication method according to claim 5,
When predetermined specific information is set in the received communication information, the relay device converts the PDU of the second protocol in the received communication information to the SDU of the PDU of the new second protocol. An information communication method comprising performing communication according to a second protocol without performing communication. A relay device installed on the communication path when transmitting and receiving communication information using a communication path between information transmitting and receiving apparatuses,
Means for extracting and storing a PDU of the first protocol from the received communication information;
Means for reading the stored PDU of the first protocol and generating a PDU of a second protocol using the PDU of the first protocol as an SDU;
Means for transmitting communication information having a PDU of the second protocol on a communication path;
Means for determining whether a reception response has arrived within a predetermined time,
Means for generating the PDU of the second protocol and retransmitting the communication information when there is no reception response, and for deleting the stored PDU of the first protocol when there is a reception response;
Means for extracting a PDU of the first protocol from the received communication information having a PDU of the second protocol, and transmitting the PDU of the first protocol to the receiving side information transmitting / receiving device via the communication path A relay device characterized by the above-mentioned. A relay device installed on the communication path when transmitting and receiving communication information using a communication path between information transmitting and receiving apparatuses,
Means for extracting and storing a PDU of the second protocol from the received communication information;
Means for reading the stored PDU of the second protocol and generating a PDU of the second protocol using the PDU of the second protocol as an SDU;
Means for transmitting communication information having a PDU of the second protocol on a communication path;
Means for determining whether a reception response has arrived within a predetermined time;
Means for generating a PDU of the second protocol and retransmitting the communication information if there is no reception response, and deleting the stored PDU of the second protocol if there is a reception response;
The PDU of the second protocol transmitted by the transmitting-side information transmitting / receiving device is extracted from the received communication information having the PDU of the second protocol, and the PDU of the second protocol is transmitted to the receiving-side information transmitting / receiving device via the communication path. A relay device having means for transmitting data to the relay device.

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