KR100654945B1 - Method and system for communicating with each other between equipments which exist in other logical network and recording media of packet transformer for the same - Google Patents

Abstract

A method is disclosed for communicating logically divided users and servers within a local network environment that constitute the same physical connection. The method converts and transmits a first unicast packet into a first broadcast packet including first address information of the first device and second address information of a destination, and then receives the first broadcast packet received by the second device. Converts the packet into a second unicast packet, converts the third unicast packet generated by the second device into a second broadcast packet including the first address information and the second address information, and transmits the packet to the first device. And converting the second broadcast packet received by the first device into a fourth unicast packet and processing the same. A unicast scheme provided by a server in which a client exists in the same local network but exists in different logical networks. Make your Internet service available.

Unicast, Broadcast, Packet, Subnet, IP Address, Internet

Description

Method and system for communicating with each other between equipments which exist in other logical network and recording media of packet transformer for the same}

1 is an explanatory diagram for explaining a conventional Internet communication method;

2 is a block diagram showing the configuration of a general IP packet,

3 is a block diagram of a communication system for explaining the Internet communication method according to the present invention;

4A to 4F are block diagrams illustrating the packet conversion procedure in order;

5 is a diagram showing the configuration of conversion reference data;

6 and 7 are block diagrams illustrating the configuration of a packet converter, respectively.

8 is a block diagram showing the configuration of a connection management module;

9 is a flowchart illustrating an overall operation of a packet converter;

10 is a flowchart illustrating an operation of a broadcast packet / unicast packet receiving module;

11 is a flowchart illustrating an operation process of a packet inspection module;

12 is a flowchart illustrating an operation of a packet recombination module;

13 is a flowchart illustrating the operation of a broadcast packet / unicast packet transmission module.

Explanation of symbols on the main parts of the drawings

210: terminal device 212: terminal program

222: first packet converter

223, 224: broadcast packet receiving module

224, 244: unicast packet receiving module

225, 245: unicast packet transmission module

226, 246: broadcast packet transmission module

227, 247: packet inspection module 228, 248: packet recombination module

229, 249: connection management module 230: server

232: server program 242: second packet converter

250a to 250f: packet 262: conversion reference data

The present invention relates to a communication method and a system thereof, and a packet converter recording medium used therein. In particular, in a local network environment, a method for enabling a user to access a server existing in different logical networks logically separated through an IP address. And a packet converter recording medium used therein.

Among the existing Internet service methods, WWW, FTP, SNMP, etc. use unicast packets such as TCP or UDP to respond to the requested service when the terminal device requests a specific service, and provide necessary data. send. At this time, in order for the terminal device and the server device to communicate, they must use a public IP address or a private IP address in the local network. do.

1 is an explanatory diagram for explaining a conventional Internet communication method, Figure 2 is a block diagram showing the configuration of a general IP packet.

1 illustrates a terminal device 110 in which a server program 130 for communication and a terminal program 112 for communication are installed. The server 130 and the terminal device 110 are provided with network interfaces 114 and 134 for communicating with other devices. In FIG. 1, only two devices are connected to each other, but in most cases, a plurality of servers 130 and terminal devices 110 are connected to each other to form a network. In order for the server 130 and the terminal device 110 to be connected through a network to communicate with each other according to an IP (internet protocol), each device must have a unique IP address that is distinct from other devices. A communication method between devices connected to a network includes a local area network method and an ATM (Asynchronus Transfer Mode) method, and a LAN method is most widely used. LAN card, which is widely used in the LAN method, is a combination of LAN, which means a local area network, and a card, which means a device used by being inserted into an expansion slot of a PC, such as a video card or a modem. LAN cards are variously referred to as network cards, Ethernet cards, Ethernet adapters, NICs (Network Interface Cards), etc., and are generally referred to as LAN cards in the present invention. Ethernet is the most widely used LAN. Terminal devices 110 or servers 130 connected to the LAN is generally equipped with a LAN card specifically designed for local area network transmission technology such as Ethernet or token ring (token ring).

There are three known methods for communicating between devices connected to a network: unicast, multicast, and broadcast. Unicast is a method of sending data to a specific device, multicast is a method of sending data to a specified number at a time, and broadcast is a method of sending data to all devices in a local area.

Except for special cases, most of them transmit and receive data in a unicast manner. The configuration of an IP packet used for unicast communication is shown in FIG. As shown in the drawing, when the unicast communication method is used, the IP packet 150 exchanged between the server 130 and the terminal device 110 is an IP header 151, a UDP / TCP header 156, and a data area 160. It consists of The IP header 151 carries information such as the sender IP address 152, the receiver IP address 153, the protocol type 154, and the like. The UDP / TCP header 156 includes the sender port number 157 and the receiver. The side port number 158 is loaded, and the user data 161 is loaded in the data area 160.

Of course, in the case of using a LAN card, information about a MAC (media access control) address indicating the unique address of the LAN card is further loaded on the front of the IP header 151. That is, when assuming communication using a LAN card, it is assumed that the media access control (MAC) address of the LAN card installed in the device to send data is (00-60-80-AA-BB-CC). Assuming that the MAC address of the LAN card installed in the network is (00-60-80-DD-EE-FF), the address of the source and destination, i.e., Media Access Control (MAC), is always in the transmitted frame for communication between two devices. The address must be included before the IP packet. In this case, therefore, the source of the Ethernet header before the IP packet 150 is written as 00-60-80-AA-BB-CC and the destination is 00-60-80-DD-EE-FF. This is the unicast communication method. In other words, the address of the receiving device is accurately written in the frame, and the receiving device has only one address.

In this way, once a PC sprinkles a unicast packet, all PCs on the local network will accept this frame and compare it with their MAC address on the LAN card.

If the LAN card MAC address is different from the destination MAC address, then the frame is discarded. This does not affect the CPU of the PC, so that the performance of the PC does not decrease.

If the destination address is compared with its MAC address, the data is sent to the CPU, and then the CPU processes the data.

Here, the MAC address is a unique address of the communication card such as a LAN card, and can determine the MAC address of the counterpart device using the IP address. Since the MAC address and the IP address are addresses for identifying the device or the communication card installed in the device, the term "device address" in the present invention includes either one or both of them.

Even if the local network has the same physical connection, most existing Internet services must be set to IP addresses capable of transmitting unicast packets. For example, a terminal device has a public IP address and a server. In the case of a private IP address or vice versa, Internet communication between the terminal and the server is not possible. In addition, even when both sides are private IP addresses in the same physical local network environment, they are composed of different subnets, so that communication between the terminal device and the server is possible even when the networks are logically divided (eg: 10.0.0.5 and 172.0.0.5, etc.). Is impossible.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for communicating between a server device and a terminal device that are not unicast communication because they are set to different logical network IP addresses in the same physical local network environment.

Another object of the present invention is to provide a system for implementing the method of the present invention.

The present invention provides a recording medium on which a packet converter necessary for implementing the method and apparatus of the present invention is recorded.

The communication method according to the present invention is a communication method between devices in the same physical local network and located in different logical networks logically separated by an IP address, the communication method being based on a signal input to the first device on the local network. Generating a first unicast packet; converting the generated first unicast packet into a first broadcast packet including first address information of the first device and second address information of a destination; Transmitting the first broadcast packet to other devices residing in the local network, receiving a broadcast packet at a second device on the local network, and receiving second address information of the received broadcast packet. Comparing the address information of the second device itself, and if the two addresses do not match, A second conversion step of discarding the received broadcast packet and converting the broadcast packet into a second unicast packet if the two compared address information match each other; referring to the information of the second unicast packet, Generating a cast packet, converting the generated third unicast packet into a second broadcast packet including the first address information and the second address information, and converting the converted second broadcast packet Transmitting a second packet to other devices in the local network, receiving a broadcast packet at the first device, the first address information included in the broadcast packet received at the first device, and the first device. Comparing own address information and the second broadcast when the first address information and the first device's own address information do not match Discard the packet and match

And a fourth conversion step of converting the second broadcast packet into a fourth unicast packet and processing the fourth unicast packet.

The step of generating the first unicast packet is performed by a first program installed in the first device, and the step of generating a third unicast packet with reference to the second unicast packet is a second device installed in the second device. Made by the program,

The first converting step and the fourth converting step are performed by a first packet converter installed in the first device, and the second converting step and the third converting step are performed by a second packet converter installed in the second device. .

In the first conversion step, in the IP header of the first unicast packet, a second address, which is a receiving side IP address, is replaced with a broadcast address, and information related to the substitution is inserted into separate first conversion reference data.

In the third conversion step, in the receiving IP header of the third unicast packet, a first address, which is a receiving IP address, is replaced with a broadcast address, and information related to the replacement is inserted as separate second conversion reference data. It is preferable.

The first converted reference data is inserted into the data area of the first unicast packet, and the second converted reference data is inserted into the data area of the third unicast packet.

The first conversion reference data includes data necessary for communication with other devices included in the first unicast packet and newly generated data.

Preferably, the second conversion reference data includes data necessary for communication with another device included in the third unicast packet and newly generated data.

The first packet converter and the second packet converter are configured to receive a broadcast receiving module for receiving a packet of a counterpart converted from a unicast packet into a broadcast packet format, and receiving a unicast packet generated by the first program or the second program. Unicast packet receiving module, Unicast packet transmitting module for transmitting a packet converted from a broadcast packet to a unicast packet to the first program or a second program, the packet converted to a broadcast packet from a unicast packet to the local network Broadcast packet transmission module for transmitting to other devices in the network, packet inspection module for checking errors in received packets, if no error after error checking of received packets Packet recombination module to create the request packet and It has a configuration having a connection management module for managing the destination and the user session.

The communication system according to the present invention is a communication system between devices in the same physical local network and in different logical networks logically separated by an IP address, the first system according to a signal installed and input on the local network. A first program for generating a unicast packet and processing a fourth unicast packet received from other devices on the local network, and the generated first unicast packet is stored in the first address information of the first device and the destination. Converts the first broadcast packet including the second address information, sends the first broadcast packet to other devices in the local network, and sends the second broadcast packet from the second device on the local network. And the first address information included in the received second broadcast packet. Compare the address information of the first device itself, and if the first address information and the address information of the first device itself do not match, discard the second broadcast packet, and if it matches, discard the second broadcast packet. A first device installed with a first packet converter for converting into a fourth unicast packet and installed on the local network to receive broadcast packets, and receive second address information of the received broadcast packet and the second device itself Compare the address information, and discard the received broadcast packet if the two compared address information does not match, and convert and generate the broadcast packet into a second unicast packet if the compared two address information match. Converting the third unicast packet into a second broadcast packet including the first address information and the second address information, and A second device having a second packet converter for transmitting the converted second broadcast packet to other devices in the local network and a second program for generating a third unicast packet by referring to information of the second unicast packet It has a configuration that includes.

The first packet converter replaces a second address, which is a receiving side IP address, with a broadcast address in the IP header of the first unicast packet, and inserts information related to the substitution into separate first conversion reference data. The second packet converter replaces the first address, which is a receiving side IP address of the third unicast packet, with a broadcast address, and inserts information related to the replacement as separate second conversion reference data.

The first converted reference data is inserted into the data area of the first unicast packet, and the second converted reference data is inserted into the data area of the third unicast packet.

The first conversion reference data includes data necessary for communication with other devices included in the first unicast packet and newly created additional data.

Preferably, the second conversion reference data includes data necessary for communication with another device included in the third unicast packet and newly generated additional data.

The first packet converter and the second packet converter are configured to receive a broadcast receiving module for receiving a packet of a counterpart converted from a unicast packet into a broadcast packet format, and receiving a unicast packet generated by the first program or the second program. Unicast packet receiving module, Unicast packet transmitting module for transmitting a packet converted from a broadcast packet to a unicast packet to the first program or a second program, the packet converted to a broadcast packet from a unicast packet to the local network Broadcast packet transmission module for transmitting to other devices in the network, packet inspection module for checking errors in received packets, if no error after error checking of received packets Packet recombination module to create the request packet and It has a configuration having a connection management module for managing the destination and the user session.

The storage medium according to the present invention includes a broadcast receiving module for receiving a packet of a counterpart converted from a unicast packet into a broadcast packet format, a first program installed in a first device on a local network, or a second program installed in a second device. Unicast packet receiving module for receiving the generated unicast packet, Unicast packet transmitting module for transmitting the packet converted from unicast packet to unicast packet to the first program or the second program, Broadcasting in unicast packet Broadcast packet transmission module for transmitting the packet converted into a packet to other devices of the local network, packet inspection module for checking an error of a received packet, and converting it into a packet form for transmission if there is no error after error checking of the received packet. Error and self-correction or retransmission request packet Creating a configuration having a recording packet converter comprising a recombinant packet module and connection management module that manages the destination and the user session of the packet.

In the present invention, the term "device" is a concept that includes not only general PCs, but also embedded devices such as machines, appliances, and equipment used in office equipment, home appliances, and various industries.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram of a communication system for explaining the Internet communication method according to the present invention, Figures 4a to 4f is an example of a configuration diagram of a packet showing the conversion process of the IP packet in order.

As shown, the terminal device 210 corresponding to the first device of the communication system 200 according to the present invention is provided with a terminal program 212 and a first packet converter 222, corresponding to the second device. The server 230 is provided with a server program 332 and a second packet converter 242, respectively.

Briefly describing the communication process in the above communication system, first, the terminal program 212 generates a first unicast packet 250a having a format as shown in FIG. 4A by a user's input to generate a first packet. The first packet converter 222 converts the first unicast packet 250a received from the terminal program 212 into a first broadcast packet 250b having a format as shown in FIG. 4B. Then send it to other devices on the local network. That is, the broadcast address "255.255.255.255" is inserted into the receiving IP address 253 of the IP header 251, and the conversion reference data 262 necessary for packet conversion is inserted into the data area 260. For example, the MAC address 262b of the network card of the server 230 set in advance as the destination of the first unicast packet 250a and the MAC address 262a of the network card of the terminal device 210 in which the terminal device 210 is installed. Etc. are inserted as conversion reference data. Since the MAC address of the counterpart in the local network can be known in advance, the MAC addresses of the counterpart devices may be provided in advance in a table form without including the MAC address in the user data area of the unicast packet. to be.

Since the packet 250a of FIG. 4A is internal communication of the terminal device, the transmitting IP address 252 and the receiving IP address 253 are the same. In this case, the connection address of the packet 250a of FIG. 4A must be previously assigned to the first packet converter 222. Even in this case, the first unicast packet 250a may be regarded as including address information to be accessed.

In some cases, it may directly have IP address information of a counterpart device to be accessed.

That is, the destination information of the first unicast packet 250a generated by the terminal program 212 is set in advance by the first packet converter 222 or the destination address information is included in the first unicast packet 250a in advance. can do. This can be configured as desired by the network designer configuring the local network.

Then, the server 230 corresponding to other devices in the local network, that is, the second device, which is one of the other devices, receives the first broadcast packet 250b and sends it to the second packet converter 242.

Then, the second packet converter 242 examines the conversion reference data 262 in the first broadcast packet 250b having a format as shown in FIG. If compared with the address, the first broadcast packet 250b is converted into a second unicast packet 250c having a format as shown in FIG. 4C.

If the two addresses are different as a result of the comparison, the first broadcast packet 250b discards it. If there is no conversion reference data 262, processing is performed as in a general broadcast signal, or the packet converters are not passed through from the beginning.

The second unicast packet 250c is delivered to the server program 232 and processed as in normal unicast communication. The server program 232 generates a third unicast packet 250d having a format as shown in FIG. 4D with reference to the second unicast packet 250c and sends it to the second packet converter 242.

The second packet converter 242 converts the third unicast packet 250d into a second multicast packet 250e in a format as shown in 4e and transmits it to other devices on the local network.

Other devices except the server 230, and the terminal device 210 corresponding to the first device belonging to it receives the second broadcast packet 250e and sends it to the first packet converter 222, the first packet The converter 222 converts the received second broadcast packet 250e into a fourth unicast packet 250f and delivers it to the terminal program 212. The terminal program 212 transmits the fourth UNI packet according to a general processing method. Process the cast packet 250f.

Of course, in the above system, general broadcast packets and unicast packets transmitted and received in the same logical network have the same logical network depending on whether the other party's IP address has a different IP address or whether there is translation reference data. Screening out the normal packets transmitted and received at, they may be configured not to process the conventional packet processing method or to go through a packet converter.

In the above process, internet communication between devices configured as different logical networks in the local network becomes possible.

In the packet conversion process according to the present invention, the unicast packets 250a and 250d generated by the respective programs 212 and 232 transmit information related to the receiving side IP address 253 as shown in FIGS. 4B and 4E. It moves to the conversion reference data 262 of the area 260, and inserts the broadcast address "255.255.255.255" into the receiving IP address 253 of the IP header 251. The TCP header 256a is converted into a UDP header 256b. The conversion reference data 262 may further record information on a receiving side IP address or MAC address, a port number, a packet length, a checksum for checking a data loss, a status flag, and a segmentation.

The broadcast packets 250b and 250e converted to the formats shown in Figs. 4B and 4E are referred to the conversion reference data 262 at the receiving apparatus again, and the unicast packets 250c, as shown in Figs. 4C and 4F. 250f). That is, the broadcast address " 255.255.255.255 " is deleted from the receiving side IP address, and the IP address 253 of the receiving side apparatus contained in the conversion reference data is waited or discarded in the packet converters 222 and 242 and the like. The UDP header 256b is also changed to the TCP header 256a.

The third unicast packet 250d is created with reference to the second unicast packet 250c, which is the same as in the conventional unicast communication method, and thus a detailed description thereof will be omitted. The process of converting the third unicast packet 250d to the second broadcast packet 250e is similar to the process of converting the first unicast packet 250a to the first broadcast packet 250b.

That is, even when the IP address is set in which the unicast packet transmission between the terminal device 210 and the server 230 is not possible in FIG. 3, the communication can be performed.

In order to convert a unicast packet into a broadcast packet, the error detection field of the original unicast packet and the conversion reference data 262 in which data necessary for communication are recorded are separated from the original user data 261. It is included in the broadcast packet. Since the unicast packet is converted into a broadcast packet, the IP header and the UDP header are changed accordingly. In the case of the TCP format, the TCP header along with the IP header is changed to the UDP header format.

For example, a packet using the packet converters 222 and 242 when the server 230 is connected may have an IP address of “10.0.2.2” and a MAC address of “00: 30: 0D: 11: 11:”. 11 ", the IP address of the server 230 is" 192.168.10.20 ", the MAC address is" 00: 30: 0D: 22: 22: 22 ", the TCP transmission / reception port of the server program 232 of the server 230 80 may be a transmission / reception port of a web browser, which is a terminal program 212 of the terminal device 210, or the like. The TCP transmit / receive port of the packet converter 222 of the terminal device 210 is 8622, the UDP transmit / receive port of the packet converter 222 is 5001, and the UDP transmit / receive of the packet converter 242 of the server 230 is used. The port may be 8621, and the TCP transmit / receive port of the packet converter 242 of the server 230 may be 5002.

5 is an example of the figure which shows the structure of the conversion reference data.

As shown in Fig. 5, the conversion reference data 262 includes a sending MAC address 262a. This is the MAC address of the transmitting device and is used as the receiving MAC address when the packet translator responds. The receiving MAC address 262b is a MAC address of the receiving apparatus and is used to determine whether the packet converter should process the packet when the packet converter receives the packet. The socket ID 262c is used to manage session information by extracting an IP address and a port number of a socket transceiver, and may be implemented by directly describing an IP address and a port number in place of the socket ID 262c. . The flag 262d is for storing a kind of command or status information necessary for transmitting / receiving a packet, and the serial number 262e should divide the packet when the size of the entire packet is large and accordingly, the order of the divided packets is sequentially The length 262e is for storing the length information of the data, and the checksum 262g is for checking the integrity of the data.

That is, the broadcast packet used in the communication method according to the present invention has both the characteristics of the conventional unicast packet and the characteristics of the conventional broadcast packet.

6 and 7 are block diagrams illustrating the configuration of a packet converter, respectively.

As can be seen in Figure 6, the packet converter (222, 242) is a broadcast packet receiving module (223, 243), unicast packet receiving module (224, 244), unicast packet transmitting module (225, 245), broadcast It is composed of a cast packet transmission module 226, 246, a packet inspection module 227, 247, a packet recombination module 228, 248 and a connection module 229, 249. Here, the broadcast packet receiving module (223, 243) is for receiving the packet of the counterpart device converted from the unicast packet format to the broadcast packet format, the unicast packet receiving module (224, 244) is a terminal program (212) Or a unicast packet generated from the server program 232. The unicast packet transmitting module 225, 245 is for transmitting its own packet converted from the broadcast packet into a unicast packet to its terminal program 212 or the server program 232, and transmitting the broadcast packet. Modules 226 and 246 are for sending their translated packets to other devices connected to the local network.

The packet inspection modules 227 and 247 are used to check whether there is an error in the received packets by using information such as a checksum included in the packet, and the packet recombination modules 228 and 248 include the receiving IP address 253. Packet conversion such as inserting the information related to the data into the conversion reference data area and inserting the broadcast address where the receiving IP address 253 existed, or performing the reverse packet conversion by referring to the conversion reference data. The connection management modules 229 and 249 are for the destination management of packets and the management of user sessions.

FIG. 7 combines the functions of the broadcast packet receiving module 223 and 243 and the unicast packet receiving module 224 and 244 of FIG. 6 into one broadcast packet / unicast packet receiving module 223a and 243a. In this case, the functions of the broadcast packet transmission module 225 and 245 and the unicast packet transmission module 226 and 246 are integrated into one broadcast packet / unicast packet transmission module 225a and 245a. The rest is the same as in FIG.

8 is a block diagram showing the configuration of a connection management module.

The connection management modules 229 and 249 described above include a send / receive address manager 229a for management of a send / receive address, a packet buffer manager 229b per user for management of a packet buffer for each user, and a packet transmit / receive. And a connection manager 229d for managing connection with the counterpart device or device programs 212 and 232 in which the counterpart device is installed.

9 is a flowchart illustrating the overall operation of the packet converter.

The packet converters 222 and 242 are in a waiting state, continuously determining whether there is a connection from other devices on the local network or from an internal program of the device in which the device is installed (step 1), and receiving a packet if there is a connection (step 1). 2).

It is determined whether the received packet is a broadcast packet or a unicast packet (step 3). If the received packet is a broadcast packet, it is checked whether there is conversion reference data 262 in the packet (step 4). If conversion reference data 262 exists in the packet, packet inspection is performed (step 5). If there is no conversion reference data, processing is performed by the conventional general broadcast packet processing method (step 6). In some cases, a packet generated when accessing a device having an IP capable of unicast communication may be configured so as not to go through a packet converter. As a result of the check in step 5, it is determined whether the packet is the correct packet (step 7). If the packet is not the correct packet, a NAK response packet is created (step 8), and a request for retransmission of the broadcast packet to the counterpart device (step 9) is performed. Go back.

On the other hand, if the check result is a correct packet, and transmits an ACK response packet to the counterpart device (step 10), and converts the broadcast packet into a unicast packet by referring to the connection management module (229, 249), conversion reference data (262) 11) The converted unicast packet is transmitted to the terminal device program 212 or the server program 232 (step 12). When transmission of the converted unicast packet is completed (step 13), it ends and waits at the starting point.

On the other hand, if the packet received in step 3 is a unicast packet, it is determined whether the destination address to be transmitted or the other party's address is capable of unicast communication with the address of the device on which it is installed (step 14). Process in the same manner as the unicast packet (step 15) and end. In this case, a packet to be generated when attempting to access a device capable of unicast communication can be determined so as not to go through a packet converter.

If the destination address to be sent or the other party's address exists in a different logical network from that of the device in which it is installed, the received unicast packet is converted into a broadcast packet by referring to the connection management module as described above (step 16). The converted packet is transmitted to other devices (step 17). When the transmission of the converted packet is completed (step 18), the controller waits for a predetermined time for an ACK response, and if there is no ACK response signal, repeats step 17 and receives an ACK response signal (step 19).

In the case of the above-described process of the present invention, Internet communication with other devices in other logical networks is possible.

10 is a flowchart illustrating an operation of a broadcast packet / unicast packet receiving module.

The broadcast packet / unicast packet receiving module 223a, 243a generates a broadcast packet / unicast packet socket upon executing the packet converters 222, 242 (step 31) to initialize the session (step 32), and the packet is received. Waiting to be received (step 33) and receiving a packet (step 34).

11 is a flowchart illustrating an operation process of a packet inspection module.

When the packet is received by the receiving module 223a or 243a, it is determined whether the packet is a broadcast packet, and if the packet is not a broadcast packet, the packet is passed to the packet recombination module 228, 248, and the packet is a broadcast packet. On the other hand (step 41), refer to the session information (step 42) to confirm the destination address (step 43), check the packet length (step 44), perform a checksum check (step 45) and check the packet serial number. (Step 46). Then, it is determined whether the received broadcast packet is the correct packet (step 47), and if it is not the correct packet, a NAK response packet is created (step 48) and a NAK response packet is transmitted to the counterpart device (step 49).

If the packet is correct, it is determined whether the packet reception is normally completed, and if the reception is not completed normally, the flow goes to step 33.

When packet reception is normally completed (step 50), an ACK response packet is created (step 51), and an ACK response packet is sent to the counterpart device (step 52).

12 is a flowchart illustrating an operation process of a packet recombination module.

The packet recombination module 228, 248 refers to the session information (step 61), creates conversion reference data (step 62), and changes the information of the IP header, the UDP header, and the TCP header (step 63). Is a unicast packet, the unicast packet is converted into a broadcast packet (step 64), the session information is updated (step 65), and the packet is converted into the broadcast packet / unicast packet transmission / reception module 225a or 245a. Pass it over.

13 is a flowchart illustrating an operation of a broadcast packet / unicast packet transmission / reception module.

The broadcast packet / unicast packet transmission / reception module 225a, 245a transmits the received packet to the destination (step 71), and when the transmission is completed (step 72) ends, waits until the packet is received again.

The communication method, the system and the packet converter recording medium according to the present invention are excellent for allowing clients, which were not previously possible, to use the unicast Internet service provided by servers in the same physical local network and separated into different logical networks. Provide effect.

Claims (12)

In a communication method between computers or other devices in different logical networks that are logically separated by IP addresses while in the same physical local network, Generating a first unicast packet according to a signal input to a first device on the local network; A first conversion step of converting the generated first unicast packet into a first broadcast packet including first address information of the first device and second address information of a destination; Sending the first broadcast packet to other devices residing in the local network; Receiving a broadcast packet at a second device on the local network; Comparing second address information of the received broadcast packet with address information of the second device itself; A second conversion step of discarding the received broadcast packet if the two compared address information do not match, and converting the broadcast packet into a second unicast packet if the compared two address information match; Generating a third unicast packet by referring to the information of the second unicast packet; A third conversion step of converting the generated third unicast packet into a second broadcast packet including the first address information and the second address information; Sending the converted second broadcast packet to other devices in the local network; Receiving a broadcast packet at the first device; Comparing the first address information included in the broadcast packet received by the first device with address information of the first device itself; A fourth conversion step of discarding the second broadcast packet if the first address information and the address information of the first device itself do not match, and converting the second broadcast packet into a fourth unicast packet if there is a match. ; And Processing the fourth unicast packet. The method of claim 1, wherein the generating of the first unicast packet is performed by a first program installed in the first apparatus, and generating the third unicast packet by referring to the second unicast packet. 2 is made by a second program installed in the device, The first converting step and the fourth converting step are performed by a first packet converter installed in the first device, and the second converting step and the third converting step are performed by a second packet converter installed in the second device. Communication method characterized in that. The method of claim 1, wherein in the first conversion step, a second address, which is a receiving IP address, is replaced with a broadcast address in the IP header of the first unicast packet, and information related to the replacement is referred to a separate first conversion. Insert it as data, In the third conversion step, in the receiving IP header of the third unicast packet, a first address, which is a receiving IP address, is replaced with a broadcast address, and information related to the replacement is inserted as separate second conversion reference data. Communication method characterized in that. The method of claim 3, wherein the first conversion reference data is inserted into the data area of the first unicast packet, and the second conversion reference data is inserted into the data area of the third unicast packet. Communication method. The data of claim 3 or 4, wherein the first conversion reference data includes data necessary for communication with other devices owned by the first unicast packet and other additional information. And the second conversion reference data includes data necessary for communication with other devices included in the third unicast packet and other additional information. The broadcast receiving module of claim 3 or 4, wherein the first packet converter and the second packet converter receive a packet of the other party converted from a unicast packet into a broadcast packet format. Unicast packet receiving module for receiving a unicast packet generated by a program; Unicast packet transmitting module for transmitting a packet converted from a broadcast packet to a unicast packet to the first program or the second program; Broadcast packet transmission module for transmitting the packet converted into a cast packet to another device of the local network, a packet inspection module for checking an error of a received packet, and converting it into a packet to be transmitted if there is no error after error checking of the received packet. And if there is a problem, write its own error correction or retransmission request packet. A packet recombination module and a connection management module for managing a destination and a user session of the packet. In a communication system between computers or devices in the same physical local network and in different logical networks logically separated by IP addresses, A first program for generating a first unicast packet according to a signal installed and input on the local network, and processing a fourth unicast packet received from other devices on the local network and the generated first unicast Converting the packet into a first broadcast packet including first address information of a first device and second address information of a destination, and transmitting the first broadcast packet to other devices in the local network, Receive a second broadcast packet from a second device on the local network, compare the first address information included in the received second broadcast packet with the address information of the first device itself, and the first If the address information and the address information of the first device itself do not match, the second broadcast packet is discarded. The first device of the first packet converter for converting a second broadcast packet into a fourth unicast packets installed; And Is installed on the local network to receive a broadcast packet, compares the second address information of the received broadcast packet with the address information of the second device itself, and if the two addresses do not match, Discarding the received broadcast packet, if the compared two address information is matched, converts the broadcast packet into a second unicast packet and the generated third unicast packet is the first address information and the second address information A third unicast by converting into a second broadcast packet included and referring to information of the second packet converter and the second unicast packet which transmits the converted second broadcast packet to other devices of the local network; And a second device having a second program for generating the packet installed therein. A communication system between devices existing in the different logical networks. 8. The method of claim 7, wherein the first packet converter replaces a second address, which is a receiving IP address, with a broadcast address in the IP header of the first unicast packet, and information related to the replacement is referred to a separate first conversion. Insert it as data, The second packet converter replaces the first address, which is a receiving side IP address of the third unicast packet, with a broadcast address, and inserts information related to the replacement into a separate second translation reference data. Communication system between devices on the same physical local network and on different logical networks. 9. The method of claim 8, wherein the first conversion reference data is inserted into a data area of the first unicast packet, and the second conversion reference data is inserted into a data area of the third unicast packet. Communication system between devices on the same physical local network and on different logical networks 10. The apparatus of claim 8 or 9, wherein the first conversion reference data includes data and other additional information necessary for communication with another device included in the first unicast packet. The second translation reference data includes data necessary for communication with other devices owned by the third unicast packet and other additional information. The device in the same physical local network and in different logical networks. Communication system between them. The broadcast receiving module according to any one of claims 7 to 9, wherein the first packet converter and the second packet converter receive a packet of the other party converted from a unicast packet into a broadcast packet format. A unicast packet receiving module for receiving a unicast packet generated by a program or a second program, a unicast packet transmitting module for transferring a packet converted from a broadcast packet to a unicast packet to the first program or the second program, A broadcast packet transmission module for transmitting a packet converted from a unicast packet to a broadcast packet to other devices in the local network, a packet inspection module for checking an error of a received packet, and if there is no error after error checking of the received packet Convert to packet type to send and request error correction or retransmission if abnormal A communication system between devices in the same physical local network and in different logical networks, comprising a packet recombination module for composing a packet and a connection management module for managing the destination and user session of the packet. Receives a unicast packet generated by a broadcast receiving module that receives a counterpart's packet converted from a unicast packet into a broadcast packet format, a first program installed in a first device on a local network, or a second program installed in a second device. A unicast packet receiving module for transmitting a packet converted from a broadcast packet to a unicast packet to the first program or a second program, and a packet converted to a broadcast packet from a unicast packet to the local program. Broadcast packet transmission module for sending to other devices in the network, packet inspection module for checking received packet errors, converts to packet form to send if there is no error after checking error of received packet, and corrects its own error if any Packet recombination module to create retransmission request packet And a packet converter including a connection management module for managing a destination of a packet and a user session.

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