JP3068511B2 - Packet relay system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet relay system for relaying packets conforming to TCP / IP (Transmission Control Protocol / Internet Protocol) specifications, and more particularly to a packet relay system for communicating between different networks via a public network. The present invention relates to a line disconnection method in a relay system.

[0002]

2. Description of the Related Art Conventionally, this type of packet relay system is used to connect a plurality of LANs (local area networks) directly or by using a wide area network (wide area network). A router, which is a type of such a connection device, is a device that connects LANs through a wide area network, analyzes a header of received data, performs routing, and transmits data to a destination LAN via a wide area network. To transfer.

[0003] In such a packet relay system using a router, a line disconnection method at the end of data transfer via a public line is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-74784. Is limited to a method in which one or a plurality of fixed timers set in advance in accordance with the contents of the protocol are used for disconnection after the maximum value has been passed.

[0004]

The above-described conventional packet relay system cannot determine which packet is the last packet, and cannot determine the end of actual communication. In the disconnect timer, the maximum value of the expected communication time is fixedly set in advance. For this reason, there have been problems such as disconnection in a state where the communication has not been completed, invalid holding of the line even after the communication has been completed, and generation of extra line cost.

An object of the present invention is to grasp the start and end of communication in communication using a public line and optimize the line disconnection time based on actual communication time and past communication time statistical information. Accordingly, it is an object of the present invention to provide a packet relay system that does not disconnect during communication and does not keep holding a line invalid.

[0006]

According to a first aspect of the present invention, there is provided a packet relay system having a routing function for transmitting data packets via a LAN (Local Area Network) and a public network by using TCP / IP (Transmission Control). (Protocol / Internet Protocol) In a packet relay system performed based on specifications, the start and end of data packet communication are identified, and a communication time is calculated from the identified start and end of the communication, and the calculated communication time is calculated. And dynamically changing the line disconnection time of the public network after the end of the communication is identified from the relationship between the communication and the average communication time of the past communication having the same communication content as the communication.

According to a second aspect of the present invention, in the first aspect of the present invention, the start and end of the communication of the data packet are started by a SYN flag in the TCP header, and ended by a FIN flag or a FIN flag in the TCP header. It is characterized by an RST flag.

A third invention is characterized in that the communication content in the first invention is a combination of a destination IP address, a source IP address, and a source port number.

In a fourth aspect of the present invention, when the communication time calculated in the third aspect of the invention is longer than the average communication time of the past communication having the same communication content as the communication, the predetermined time after the end of the communication is identified. No other packet having the same communication content has been generated on the public line until the shortest disconnection time has elapsed, and another packet different from the communication content has occurred on the public line when the shortest disconnection time has elapsed. And disconnecting the line of the public network on condition that there is no public network.

According to a fifth aspect of the present invention, when the communication time calculated in the third aspect of the invention is shorter than an average communication time of a past communication having the same communication content as the communication, a predetermined time after the end of the communication is determined. No other packet having the same communication content has been generated on the public line until the predetermined shortest disconnection time has elapsed, and another packet different from the communication content has been generated on the public line when the predetermined maximum disconnection time has elapsed. It is characterized in that the line of the public network is cut off on the condition that no occurrence has occurred.

A sixth invention is characterized in that the shortest disconnection time in the fourth and fifth inventions is predetermined in correspondence with the communication content.

A seventh invention is characterized in that the longest disconnection time in the fifth invention is predetermined in correspondence with the communication content.

[Operation] By recognizing a protocol identifier set in a packet transmitted / received during communication and detecting a flag set inside the communication protocol, the start and end of the communication are confirmed. Then, the actual communication time is calculated accordingly.

On the other hand, the accumulated total communication time, the total number of communication times, and the average communication time are calculated and stored as past statistical information for each communication content (a combination of a destination IP address, a transmission source IP address, and a transmission source port number). .

[0015] The disconnection timer for disconnecting the public line after confirming the end of communication is dynamically changed from the magnitude relation between the calculated communication time and the average communication time based on the past statistics regarding the communication having the same communication contents as this communication. I do.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a system configuration diagram showing one embodiment of the present invention, and FIGS. 2 and 3 are processing flowcharts showing one embodiment of the present invention.

Referring to FIG. 1, the present invention comprises a routing processing unit 101 for storing, transmitting and receiving packets.
A LAN interface unit 102 and a line interface unit 103 for transmitting a packet to the routing processing unit 101 or receiving a packet from the routing processing unit 101;
A packet start detector 104 for extracting the start of communication and the port number of the packet, a system clock 105 for counting the system time, a communication state management table 106 for storing the communication state, and a packet for detecting the end of communication of the packet An end detection unit 107, an end timer 108 referred to for disconnecting the line, a basic information table 109 in which basic data for disconnecting the line are registered in advance, and a communication status from the time of operation of the system to the present are stored. And a statistical information processing unit 111 for calculating statistical information.

Next, the operation of the embodiment of the present invention will be described in detail with reference to FIGS. The packet handled by the present invention is based on the TCP / IP specification.

FIG. 4 is a detailed block diagram of the routing processing unit 101. Packets input from the LAN interface 102 and the line interface 103 are stored in the buffer memory 1013. Central processing unit 1011
Recognizes the IP address of the packet stored in the buffer memory 1013 based on the information of the routing table 1012 registered in advance from a terminal device (not shown), and delivers the packet to an appropriate interface. The input / output memory 1014 is used to exchange data with the packet end detection unit 107 and the statistical information processing unit 111.

The packet start detecting unit 104 in FIG.
Is constantly monitoring the contents of the packets stored in the buffer memory 1013, and the destination IP of the stored packets is
The address, source IP address, and source port number 401 and SYN flag 402 of the TCP header shown in FIG. 4 are monitored (S1).

When the packet start detection unit 104 recognizes that the SYN flag in the TCP header of the packet stored in the buffer memory 1013 is 1, information of the packet is extracted and the information is written in the communication state management table 106. .

FIG. 6 shows details of the information stored in the communication state management table 106. Packet start detection unit 1
04 recognizes that the SYN flag of the TCP header of the packet is 1, extracts the destination IP address, the source IP address, and the source port number of the packet,
Write from the top of the table. Also, when writing information to the communication state management table 106, the packet start detection unit extracts the current time together with the system clock 105 and writes the information (S2).

The system clock 105 is preset by a terminal device (not shown) when the system is started.

FIG. 6 shows an example in which FTP (File Transfer Protocol) is stored in table number 1.

Similarly to the packet start detecting unit 104, the packet end detecting unit 107 constantly monitors the packet input to the buffer memory 1013 of the routing processing unit 101. When the FIN flag 403 and the RST flag 404 in FIG. It is monitored whether an input has been made (S3).

When the end-of-packet detection unit 107 detects that 1 has been input to the FIN flag 403 or the RST flag 404, it recognizes that communication has ended, and determines the destination IP address and source of the packet in which the flag was detected. I
The P address and the source port number are detected (S4).

After that, the packet end detecting section 107 searches the communication state management table 106 based on the detected information, and recognizes the corresponding information. Further, the packet end detecting unit 107 extracts the storage position information of the information recognized in the communication state management table 106, and interrupts the central processing unit 1011 of the routing processing unit 101 indicating the end of the communication, and at the same time, simultaneously executes the interruption indicating the communication end Is output as the storage position information of the communication state management table 106 corresponding to (S)
5). In the present embodiment, the communication status management table 10
The storage position information of 6 becomes 1, and 1 is output to the input / output memory 1014.

Further, the packet end detecting section 107
A pulse is sent to the end timer 108. End timer 108 receiving a pulse from packet end detection section 107
Starts timing (S6).

The central processing unit 101 of the routing processing unit 101 having received an interrupt from the packet end detection unit 107
1 recognizes the current time information from the system clock 105 and, at the same time, recognizes the corresponding information from the communication information management table 106 based on the storage position information in the input / output memory 1014 (S7).

The central processing unit 1011 recognizing the address information, the port number, and the time information sends the basic information table 10
9 are searched for (S8).

FIG. 7 shows details of information registered in the basic information table 109. The basic information table 109 includes a destination IP address, a source IP address, a source port number, a shortest disconnection time 1091, and a longest disconnection time 109.
2. Statistical information reference number 1093 is registered in advance from a terminal device (not shown) when the system is started. The shortest disconnection time 1091 is a minimum monitoring time from when the packet end detection unit 107 detects the end of communication to when the line is disconnected. The longest disconnection time 1092 indicates the time for monitoring the maximum communication state when the average communication time is shorter than this time (details will be described later).

The value of the shortest disconnection time 1091, the longest disconnection time 1092, and the statistical information reference number 1093 is registered by the system administrator, judging from the type of the destination and the terminal of the transmission source, the past communication results, and the like. In this embodiment, since the destination IP address, source IP address, and source port number are FTP, the shortest disconnection time 1091
5 seconds, the longest cutting time 1092 is 30 seconds, and the statistical information reference number 1093 is 3.

After finishing searching the basic information table 109, the central processing unit 1011 refers to the shortest cutting time from the corresponding information in the basic information table (S9).

Thereafter, the central processing unit 1011 confirms whether or not a packet having the information for which the disconnection process is currently to be performed is generated from the packet start detection unit 104 (the same communication may be continuously performed) (S10). Compare the end timer 108 with the shortest disconnection time 1091 (S1
1).

If a corresponding packet is generated during that time, the end timer 108 is stopped and cleared, and the state returns to the monitoring state again (S12).

The value of the end timer 108 is set to the shortest disconnection time 10
If it is equal to 91, the central processing unit 1011
Refers to the corresponding statistical information reference number 1093 in the basic information table 109 (S13). In this embodiment, the value 3 is recognized as the statistical information reference number when the value of the end timer 108 reaches 5 seconds because no corresponding new packet has been generated.

FIG. 8 shows the details of the statistical information table 110. (A) shows information before the start of communication, and (b) shows information whose registered contents have been changed after the end of communication. The statistical information table 110 has a statistical information table number 110 corresponding to the statistical information reference number 1093 of the basic information table 109.
1, the total number of communication times counted since the system was started 11
02, the total communication time 1103, and the average communication time 1104 calculated from the total communication time 1102 and the total communication time 1103 are stored.

The central processing unit 1011 of the routing processing unit 101 searches the statistical information table number 1101 of the statistical information table 110 from the statistical information reference number 1093, and refers to the average communication time 1104 (S14).

In this embodiment, the statistical information table number is determined to be 3 in FIG.
102 is determined 26 times, the total communication time 1103 is determined to be 8790 seconds, and the average communication time 1104 is determined to be 338 seconds.

Thereafter, the central processing unit 1011 sends the current detected communication based on the time when the packet end detection unit 107 interrupted and the communication start time stored in the corresponding item of the communication state management table 106. Is calculated (S15), and compared with the average communication time 1104 (S16).

At this time, if the communication time is longer than the average communication time, the central processing unit 1011 recognizes that the communication is completed.

If the communication time is short as a result of the comparison,
The longest disconnection is performed while confirming whether or not a packet (a packet having the same destination IP address, source IP address, and source port number) having information to be disconnected currently is generated from the packet start detection unit 104 (S17). A comparison is made with time 1092 (S18).

If a corresponding packet is generated during that time, the end timer 108 is stopped and cleared, and the monitor returns to the monitoring state again.

The value of the end timer 108 is set to the maximum disconnection time of 10
If it is equal to 92, the central processing unit 1011
Recognizes that the communication is completed. At the same time, the central control device 1011 again refers to the communication state management table 106 (S19).

If another entry (a packet using the same line but different destination IP address, source IP address, and source port number) exists in the communication status management table 106, the communication is continued. If monitoring is not performed, a disconnection instruction is issued to the line interface 103 (S20).

When the end of communication is determined, the central processing unit 1011 stops and clears the end timer 108 (S2).
1). At the same time, the communication time calculated this time is output to the input / output memory 1014 (S22). In this embodiment, since no other communication is registered in the communication state management table 106, the current communication time of 400 seconds is output to the input / output memory 1014.

The statistical information processing section 111 has an input / output memory 1
014 is monitored, and when the communication time is output, 1 is added to the total number of times of communication 1102 and written in the statistical information table 110 as a new total number of times of communication (S23). At the same time, the communication time output to the input / output memory 1104 is added to the total communication time 1103 and written to the statistical information table 110 (S24). Further, the statistical information processing unit 111 calculates an average communication time based on the newly written total communication count 1102 and total communication time 1103, and writes the average communication time in the statistical information table 111 (S25).

In this embodiment, as shown in FIG. 8B, the total number of communication times is 27 and the total communication time is 919.
Since it is 0 second, 340 seconds is written as the new average communication time as the average communication time.

As described above, each time communication is performed, the information is reflected as statistical information, and is applied to the next communication. For this reason, since the optimal line disconnection time is determined according to the type of communication, the invalid line holding time of the public network is reduced as compared with the conventional fixed timer, thereby reducing the line charge and the line usage. Efficiency can be increased.

[0051]

As described above, the packet relay system of the present invention grasps the start and end of communication and optimizes the line disconnection time based on the actual communication time and past statistical information. By doing so, it is possible to prevent disconnection during communication or to keep the line invalidly held, thereby improving serviceability and optimizing communication charges and improving line use efficiency.

[Brief description of the drawings]

FIG. 1 is a system configuration diagram showing an embodiment of the present invention.

FIG. 2 is a processing flowchart illustrating an embodiment of the present invention.

FIG. 3 is a processing flowchart subsequent to FIG. 2;

FIG. 4 is a block diagram of a routing processing unit according to the present invention.

FIG. 5 is a schematic diagram showing a format of a TCP header.

FIG. 6 is a diagram illustrating a configuration example of a communication state management table according to the present invention.

FIG. 7 is a diagram showing a configuration example of a basic information table according to the present invention.

FIGS. 8A and 8B are diagrams illustrating a configuration example of a statistical information table according to the present invention, wherein FIG. 8A illustrates a state before information update and FIG. 8B illustrates a state after information update.

[Explanation of symbols]

 101 routing processing unit 1011 central processing unit 1012 routing table 1013 buffer memory 1014 input / output memory 102 LAN interface unit 103 line interface unit 104 packet start detection unit 105 system clock 106 communication state management table 107 packet end detection unit 108 end timer 109 basic information Table 1091 Shortest disconnection time 1092 Longest disconnection time 1093 Statistical information reference number 110 Statistical information table 1101 Statistical information table number 1102 Total communication count 1103 Total communication time 1104 Average communication time 111 Statistical information processing unit 401 Source port number 402 SYN flag 403 FIN Flag 404 RST flag

Continuation of the front page (56) References JP-A-7-336392 (JP, A) JP-A-8-8917 (JP, A)

Claims (7)

(57) [Claims] 1. A LAN (local area network)
And a routing function for transmitting data packets via the public network with TCP / IP (transmission
In a packet relay system performed based on a control protocol / internet protocol) specification, a start and an end of communication of a data packet are identified, a communication time is calculated from the identified start and end of the communication, and the calculated communication is calculated. A packet relay system characterized by dynamically changing a line disconnection time of the public network after the end of the communication is identified based on a relationship between time and an average communication time of past communication having the same communication content as the communication. 2. The communication system according to claim 1, wherein the start and the end of the communication of the data packet are started by a SYN flag in the TCP header, and the end is started by a FIN flag or an RST flag in the TCP header. The packet relay system according to the above. 3. The packet relay system according to claim 1, wherein the communication content is a combination of a destination IP address, a source IP address, and a source port number. 4. When the calculated communication time is longer than the average communication time of past communication having the same communication content as the communication, the public communication is continued until a predetermined shortest disconnection time elapses after the end of the communication is identified. The line of the public network is provided on the condition that no other packet identical to the communication content has occurred on the line and no other packet different from the communication content has occurred on the public line when the shortest disconnection time has elapsed. The packet relay system according to claim 3, wherein the packet is disconnected. 5. When the calculated communication time is shorter than the average communication time of past communication having the same communication content as the communication, the public communication is continued until a predetermined shortest disconnection time elapses after the end of the communication is identified. On the condition that no other packet identical to the communication content has occurred on the line and no other packet different from the communication content has occurred on the public line when a predetermined maximum disconnection time has elapsed. 4. The packet relay system according to claim 3, wherein said line is disconnected. 6. The communication system according to claim 4, wherein the shortest disconnection time is predetermined in correspondence with the communication content.
The packet relay system according to the above. 7. The packet relay system according to claim 5, wherein said longest disconnection time is predetermined in correspondence with said communication contents.