JPH0443736A - Lan connector and inter-lan connection structure - Google Patents

Abstract

PURPOSE:To promote multi-vendor of a LAN connector and to realize economy by constituting the system with a local area network (LAN) address recognition section and a communication protocol control section. CONSTITUTION:The system consists of a LAN address recognition section 10 including a device receiving a frame flowing in a LAN and a detecting whether or not a frame is a frame to be sent to other LAN based on an opposite address and a communication protocol control section 30 including a device establishing a call with other LAN connector via a packet exchange network with the CCITT (The International Telegraph and Telephone Consultative Committee) recommendations X.25 protocol and inserting a data of a frame detected by the LAN address recognition section 10 into an information packet of the X.25 protocol and transferring the resulting data. Thus, LANs are connected via a packet exchange network and the data is transferred by the X.25 protocol, the line utilization charge is reduced for the user of low traffic and the multi-vendor of the LAN connectors opposite to each other is promoted and more economical network is built up.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention provides a LAN connection device suitable for using a packet switching network to interconnect LANs, and a method for connecting LANs using this LAN connection device. Regarding connection structure.

C. Conventional technology] Traditionally, LANs were installed in geographically separated locations.
(Local Area Network; local area communication w4) When connecting two networks to each other, they were connected via a high-speed digital private line 1-hour side line loading device.

[TJB that the invention attempts to solve] Since it is a leased line connection, it was possible to connect to a LAN in a remote location using a unique protocol determined by the LAN system owner, but because it is a leased line, it is difficult for users with low traffic to connect. However, since the line usage fee is expensive, and the data transfer protocol is unique, it is difficult to use multiple vendors for opposing LAN connection devices, making it difficult to achieve economic efficiency.

The present invention has solved these drawbacks, and its purpose is to provide a LAN connection device suitable for interconnecting LANs via a packet switching network and an inter-LAN connection structure using this LAN connection device. It is about providing.

[Means to solve the problem]

The LAN connection device of the present invention includes a LAN address recognition section including a mechanism for receiving frames flowing through a LAN and detecting whether or not the frame should be sent to another LAN based on the destination address, and a CCITT (International Telegraph and Telephone Advisory Committee) Recommendation X. Other L via packet switching network in 25 steps
After establishing a call with the AN connection device, The communication protocol control section includes a mechanism for inserting data (other party's address, message, etc.) in a frame detected by the LAN address recognition section into an information packet of 25 procedures and transferring the data.

Further, the communication protocol control unit includes a mechanism for receiving information packets of X, 25 procedures via the packet switching network, and the LAN address recognition unit recognizes the data (destination address, Messages, etc.) are sent to the LAN in LAN frame format.

The LAN connection structure according to the present invention has a structure in which a LAN connection device having the above configuration is connected to each of the LANs to be connected to each other, and each LAN connection device is connected via a packet switching network.

[Operation] In the present invention, for example, the first LAN and the second LAN
When connecting the first LAN and the second LAN, a LAN connection device is connected to both the first LAN and the second LAN, and each LAN connection device is accommodated as a subscriber in the packet switching network, for example, a LAN connected to the first LAN. When transferring data from a terminal to a LAN terminal connected to a second LAN, the first LAN
A LAN address recognition unit in a LAN connection device connected to the first LAN receives all frames flowing through the first LAN, detects whether or not the frame should be transferred to the second LAN based on the destination address, and detects whether or not the frame should be transferred to the second LAN, and The control part is
, after establishing a call with the LAN connection device connected to the second LAN via the packet switching network in step 25 x
The data in the frame detected by the LAN address recognition unit (other party's address, message, etc.) is inserted into the information packet of the 925 procedure, and transferred to the LAN connected to the second LAN.
The communication protocol control unit in the AN connection device receives the above information packet of the An operation such as sending the message to the second LAN in LAN frame format is performed, and the message is sent to the LAN on the second LAN.
Delivered to your device.

[Example] Next, an example of the present invention will be described in detail with reference to the drawings.

First, referring to FIG. 1, an LA according to an embodiment of the present invention will be explained.
The N-to-N connection structure will be explained.

The LAN-to-LAN connection structure shown in FIG. Device 3 is connected and the other bus type L
A LAN connection device 5 similar to the LAN connection device 3 is connected to the AN system 6 . Each LAN connection device 3.5 is accommodated as a subscriber of the packet switching network (public packet switching network) 4, and a virtual communication 'lIr8 is set up in the packet switching network as described later, and this virtual LAN connection device 3 and LAN connection device 5 using communication path 8
Data is transferred between the two. Note that a LAN terminal 1.7 is connected to each of the bus-type LAN systems 2 and 6.

Next, the configuration of an embodiment of the LAN connection device 3.5 will be described with reference to FIG.

As shown in FIG. 2, the LAN connection device of this embodiment is -
It is composed of two subsystems: a LAN address recognition section 10 shown by a dashed dotted line, and a communication protocol control section 30 shown by a dashed double dotted line connected to this by an internal bus 40. Bus-type LAN in Figure 1
It is connected to a bus type cable 50 that constitutes the system 2 or 6.

Inside the LAN address recognition recognition unit 0, there is a transmission/reception frame 1I11 that separates and multiplexes the transmission/reception frames.
/Multiplex circuit 11 is a signal line! ! , 1 are connected to the branching device 51. Signal line! 2 transmits the received signal separated by the transmitting/receiving frame separation/multiplexing circuit 11, and is connected to the LAN.
It is connected to the frame detection circuit 12. The LAN frame detection circuit 12 recognizes the unique LAN frame of the LAN system from the received signal input from the signal line i2, and sends the other party's address included in the frame to the LAN frame via the signal line 25.
A signal (received signal) containing the other party's address and the message to be transmitted using the LAN frame is output to one input terminal of the N address comparison circuit 13 and is sent to the signal line 14.
This is a circuit that outputs the signal to one input terminal of the gate circuit 15.

The LAN address memory 14 stores the LA that the LAN address recognition unit 10 attempts to capture from the bus type cable 50.
This is a memory that holds the destination address included in the N frame, and the destination address held here is outputted to the other input terminal of the LAN address comparison circuit 13 via the signal line 16. The LAN address comparison circuit 13 outputs the partner address detected by the LAN frame detection circuit 12 as a signal 'g! 5
By inputting the other party's address held in the LAN address memory 14 through the signal line 16 and comparing the two, it is possible to determine whether the LAN frame detected this time by the LAN frame detection circuit 12 is the L to be sent to another LAN.
This is a circuit that determines whether or not it is an AN frame. The determination result is input to the other input terminal of the gate circuit 15 by the signal [7.

The gate circuit 815 connects the signal line 14 when the comparison result transmitted from the signal line 17 indicates a match, that is, when the partner address in the detected LAN frame and the partner address held in the LAN address memory 14 match. The contents are taken out as they are to the signal line 18 and sent to the received data holding circuit 16.
This is the circuit that sends the signal to. The received data holding circuit 16 is a circuit that stores the data output from the gate circuit 15.

On the other hand, the transmission data holding circuit 17 is a circuit that holds the transmission data sent from the communication protocol control section 30, and this held transmission data is transmitted to the LAN frame generation circuit 18 via the signal line 19. LAN frame generation time! 18 is a signal! LA containing the transmission data input from A9
This is a circuit that generates N frames, and the generated LAN frames are given to the ml/multiplex circuit 11 for transmitting/receiving frames by a signal 13, and are sent to the signal line! ! 1 and branching device 5] onto the bus-type table 50.

LAN address memory 14 in the LAN address recognition section 10. The received data holding circuit 1ε and the transmitted data holding circuit 17 are connected to the internal bus 40 by signal lines flO, fll and 7!12.

Next is the communication protocol system? In the first section 30, a communication system m circuit 31. A microprocessor sensor circuit 33, a program/data memory circuit 34, and a level conversion circuit 32 are provided. The program/data memory circuit 34 is a memory that holds programs and various data that determine the operation of the microprocessor circuit 33, and receives the signal Lj! 15
It is connected to the device internal bus 40 by. The microprocessor sensor circuit 33 is a circuit that executes predetermined processing according to the program stored in the program/data memory circuit 34, and when connected to the internal bus 40 by the signal jJf 14, the microprocessor sensor circuit 33 is connected to the internal bus 40 by the signal jJf14. ! 17, it is connected to a maintenance terminal 36. Note that this maintenance terminal 36 is used to perform various controls related to the maintenance of the LAN connection device.
LAN address memory 14 in the AN address recognition unit 10
The storage of the address to X.X is performed from this maintenance terminal 36, and the communication control circuit 31 25 data link layer, physical layer (assignment of flag pattern, “o” insertion, CRC (
This circuit executes procedures such as assigning a cyclic redundancy code, etc.), and is connected to the internal bus 40 by a signal line 113 and to the level conversion circuit 32 by a signal line ff116. Level conversion circuit 32
is connected to the subscriber line 35 of the packet switching network 4 shown in FIG.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be explained as follows.
A case will be described below using an example in which a message is transferred from a LAN terminal 1 connected to a bus-type LAN system 2 to a LAN terminal 7 connected to a bus-type LAN system 6.

When the LAN connection devices 3 and 5 shown in FIG. 1 are powered on, a virtual call is set up according to the following procedure. First of all,
Microprocessor circuit 33 of one LAN connection device 3
sends a call setup request packet from the communication control circuit 31 to the subscriber side 1s35 of the packet exchange m4 via the level conversion circuit 32 in accordance with the procedure defined in X.25. This call setup request packet contains the LA determined by the packet switching network 4.
The incoming call number of the N connection device 5 is assigned.

The packet switching network 4 analyzes the called number in the above call setup request packet, and sends the called call request packet to the LAN connection device 5.

When the microprocessor circuit 33 of the LAN connection device 5 receives an incoming request packet from the packet switching network 4 via the level conversion circuit 32 and the communication control door jB31, if it is in a state where normal operation is possible, the microprocessor circuit 33 sends the response packet to the communication control circuit. 31 and the level conversion circuit 32, and then sent back to the packet switching network 4.

In response to this, the packet switching network 4 sends the response packet to the LAN.
It is sent back to the connecting device 3.

With the above steps, the setting of the virtual call is completed, and the virtual communication channel 8 shown in FIG. 1 is established.

With the virtual communication channel 8 established as described above, a LAN frame containing a message addressed to the LAN terminal 7 of the bus-type LAN system 6 located at a remote location from the LAN terminal 1 of the bus-type LAN system 2 shown in FIG. is sent, its L
The message in the AN frame is sent to the LAN as follows.
Delivered to terminal 7. Here, the address of the LAN terminal is α, and this address α has been previously sent from the maintenance terminal 36 to the L
It is assumed that the data is input to the microprocessor circuit 33 of the AN connection device 3 and written to the LAN address memory 14 through the device internal bus 4o under its control.

A LAN frame sent from the LAN terminal 1 is transmitted by a bus type cable 50.

The transmit/receive frame ji1/multiplex circuit 11 in the LAN address recognition section 10 of the LAN connection device 3 receives all the LAN frames on the bus type cable 50 via the branch device 51 and the signal line 11, and sends them via the signal #f2. LA
It is output to the N frame detection circuit 12.

The LAN frame detection circuit 12 detects one LAN frame as a signal line! 2, the other party's address included therein is extracted and outputted to the LAN address comparison circuit 13 via the signal line 25, and the content of the LAN frame including the other party's address and message is sent to the signal line 25. 1
4 to the gate circuit 15.

The LAN address comparison circuit 13 is connected to the signal line ! from the LAN frame detection circuit 12. 5 is compared with the address α added from the LAN address memory 14 via the signal line 16, and if they match, the signal line 17 is set to a logical value "L", and the gate circuit 15 is a signal line when the logic value of signal line 17 becomes "B"!!
4 through the signal line 18 to the data holding circuit 1.
Output to 6. Therefore, if the LAN frame detected this time by the LAN frame detection circuit 12 is addressed to the LAN terminal 7 sent from the LAN terminal 1 and the destination address therein is α, the gate circuit 15 is opened. The contents of the LAN frame are input to the received data holding circuit 16 and stored there. Note that if the addresses do not match, that is, LAN 1 end 1 is a bus type LAN.
If a LAN frame, etc. addressed to another LAN terminal (not shown) connected to system 2 is sent, that LAN
N frames are ignored.

On the other hand, when the data is accumulated in the received data holding circuit 16, the microprocessor circuit 33 of the communication protocol control unit 30 reads the data through the internal bus 40 and converts the received data into the information packet format of CCITT Recommendation X, 25. It is assembled and output to the communication control circuit 31 through the internal bus 40.

The communication control circuit 31 transmits CCI to the above information packet.
Execute the data link layer and physical layer procedures of TT Recommendation X, 25. Then, the level conversion circuit 32 converts the electrical level of the output of the communication control circuit 31 to a level that can be connected to the packet switching network 4, and sends it to the subscriber line 35 of the packet switching network 4.

This sent information packet is sent to the destination L by the packet switching network 4 through the virtual communication 1IIB in FIG.
The data is transferred to the AN connection device 5.

The transferred information packets are transferred to the subscriber line 35. of the LAN connection device 5. Communication control circuit 31 through level conversion circuit 32
is maintained. Thereafter, the microprocessor circuit 33 in the fixed unit f5 receives the information packet held in the communication control circuit 31 via the internal bus 40, and transmits the destination address α and the message contained in the packet to the bus type LAN system 6. The format is set at an appropriate position to generate transmission data, and then the generated transmission data is sent to the transmission data holding circuit 1 via the internal bus 40.
Transfer to 7.

LAN frame generation circuit 1 of LAN address recognition unit 10
8 receives the transmission data from the transmission data holding circuit 17 via the signal line 29 when transmission is possible, generates a LAN frame by adding a LAN frame pattern, and sends it to the transmission/reception frame separation/multiplexing circuit 11.

The transmission/reception frame portion 11/multiplexing circuit 11 sends the LAN frame generated by the LAN frame generation circuit 18 to the branching device 5.
1 and send it out onto the bus burner 50.

This LAN frame is a LAN that matches the destination address α.
It is received by terminal 7.

As described above, a message is delivered from the LAN terminal 1 to the LAN terminal 7.

The above operation is performed when the LAN connection device 3.5 connects to each CCI.
TT Recommendation X. D T E (DataTe
rminal equipment) and DCE
(Data Control-qujpmen
t), but by providing a procedure for sending a call setup request packet to the LAN connection device 5, a virtual call can be setup from either side.

[Effects of the Invention] As explained above, according to the present invention, LANs installed in geographically distant places can be connected to each other via a packet switching network, and a virtual communication channel set in the packet switching network can be connected to each other via a packet switching network. Since data is transferred using the Interconnection structure can be provided.

In addition, the LAN connection device receives frames flowing through the LAN, detects whether the frame should be sent to another LAN based on the destination address, and sends it to the packet switching network, so data is actually transferred. A LAN terminal can transfer data using the same procedure without distinguishing between a LAN terminal connected to its own LAN and a LAN terminal connected to another LAN.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of a LAN connection structure according to the present invention, and FIG. 2 is a functional block diagram of an embodiment of a LAN connection device. In the figure, 1.7... LAN terminal 2.6... Bus type LAN system 3.5... LAN connection device 4... Packet switching network 8... Virtual communication path 10... LAN address Recognition unit 11... Transmission/reception frame II/multiplex circuit 12...
LAN frame detection circuit 13...LAN address comparison circuit 14...LAN address memory 15...Gate circuit 16...Received data holding circuit 17...Transmission data holding circuit 1st...LAN frame generation circuit 30... Communication protocol control unit 31... Communication control circuit 32... Level conversion circuit 33... Microprocessor circuit 34... Program/data memory circuit 35... Subscriber line 36 of the packet switching network ...Maintenance terminal 40...Internal bus 50...Bus type cable 51...Branch device

Claims (3)

[Claims] (1) A LAN address recognition unit including a mechanism that receives a frame flowing through the LAN and detects whether the frame should be sent to another LAN based on the destination address; After establishing a call with another LAN connection device via the packet switching network in the X.25 procedure, 2. A LAN connection device comprising a communication protocol control unit including a mechanism for inserting and transmitting data in a frame detected by the LAN address recognition unit into an information packet of 25 procedures. (2) The communication protocol control unit transmits the X. 2. The information packet according to claim 1, further comprising a mechanism for receiving an information packet of 25 procedures, and wherein the LAN address recognition unit includes a mechanism for transmitting data included in the information packet received by the communication protocol control unit to the LAN in a LAN frame format. LAN connection device. (3) An inter-LAN connection structure having a structure in which the LAN connection device according to claim 2 is connected to each of the LANs to be connected to each other, and each LAN connection device is connected via a packet switching network.