JPH04156134A - Transceiver for bus type lan - Google Patents

Abstract

PURPOSE:To improve the use efficiency of transmission lines by providing a switch control means which divides one transmission line, to which the terminal of the other party to and from which a local terminal transmits and receives data is connected, and the other transmission line in accordance with comparison results of comparing means and controls switching of switch means to terminate the other transmission line. CONSTITUTION:When the local terminal transmits and receives data, one of transmission lines 20a and 20b to which the terminal of the other party is connected is discriminated by comparing means 62, 65, and 66, and a switch control means 63 switches switch means SW1 to SW4 in accordance with comparison results to divide both transmission lines 20a and 20b and terminates the other transmission line to which the terminal of the other party is not connected. Thus, another terminal can use the other transmission line to transmit data, and the use efficiency of transmission lines is improved.

Description

[Detailed Description of the Invention] [Summary] Regarding a bus-type LAN transceiver that connects a bus-type LAN transmission line and a terminal, the transmission line can be divided and data can be transmitted from each terminal to each other, thereby improving the efficiency of using the transmission line. In a bus-type LAN transceiver that connects a terminal to the transmission path in a bus-type LAN in which a transmitting terminal occupies the transmission path, a switch means for connecting or dividing the transmission path connected on both sides is provided. And the destination address or source address in the transmitted/received data and the address of the own terminal on which side of the transmission line connected to both sides of the transmission path the other terminal that is transmitting and receiving from the own terminal connected to itself and a comparison means that determines the difference between the transmission line on one side and the transmission line on the other side connected to the other terminal that is transmitting and receiving from the terminal based on the comparison result of the comparison means. and a switch control means j for controlling switching of the switch means so as to terminate the transmission line on the other side.

[Industrial application field]

The present invention relates to a bus-type LAN transceiver, and relates to a bus-type LAN transceiver.
The present invention relates to a bus-type LrN transceiver that connects an AN transmission path and a terminal.

[Conventional technology]

Conventionally, as shown in FIG.
There is a bus-type LAN in which the main transmission line 12 is connected to the main transmission line 12 by transceivers lla to llb.

CS MA/CD (Carrier Multip
le Access with Co11isio
For example, when data is being transmitted from a terminal 10a to a terminal 10e in a bus-type LAN using the n Detection method, the data from this terminal 10a occupies the transmission line 12 and transmits data from another terminal. Transmission to route 12 is prohibited.

No. [Problem to be Solved by the Invention] In the conventional C3MA/CD bus type LAN, for example, when data is transmitted from terminal 10a to terminal 10e, even if a data transmission request occurs from terminal 10d to terminal 10b, this data is The transmission had to wait until the data transmission from the terminal 10a to the terminal 10e was completed, and there was a problem that the efficiency of using the transmission line 12 was poor.

The present invention has been made in view of the above points, and an object of the present invention is to provide a bus-type LAN transceiver that divides the transmission path and sends data from separate terminals to each, thereby improving the efficiency of using the transmission path. shall be.

[Means for Solving the Problems] The bus-type LAN transceiver of the present invention connects the terminal to the transmission path by the bus YLAN that occupies the transmission path or the terminal that performs transmission, and the bus-type LAN transceiver connects the terminal to the transmission path by connecting the terminal to the transmission path. A switch means for connecting or splitting transmission lines connected to one another, and a destination in the transmitted/received data to indicate which side of the transmission line connected on both sides the other terminal that is transmitting and receiving from the own terminal connected to itself is on the other side. A comparison means for comparing and determining the address or source address and the address of the own terminal, and a transmission line on one side to which the other terminal to which the own terminal is transmitting/receiving is connected, based on the comparison result of the comparison means, and the other side. and switch control means for controlling switching of the switch means so as to divide the transmission line on one side and terminate the transmission line on the other side.

[Effect]

In the present invention, when the own terminal is transmitting and receiving, the comparison means determines which of the transmission lines on both sides the other terminal is on, and the switch control means switches the switch means according to the comparison result. Then, the transmission lines on both sides are divided, and the transmission line on the other side, which is not connected to the other party's terminal, is terminated. Therefore, another terminal can perform data transmission on the transmission path on the other side, improving the efficiency of using the transmission path.

〔Example〕

FIG. 1 shows a block diagram of one embodiment of the transceiver of the present invention.

In the figure, each of the transmission lines 20a and 20b is a connector (CN).
It is connected to the internal transmission line 23 via 21 and 22.

The internal transmission path 23 is a switch SWI.

Each SW2 is divided into three parts, and Ethernet interfaces 24, 25, and 28 are connected to each part.

Each of the switches 5W3PSW4 is connected to CN2 of the internal transmission line 23.
1 side and CN22 side are terminated.

Here, the frame format of the data transmitted through the transmission paths 20a and 20b is as shown in Fig. 2, which includes a frame start delimiter (SFD) following the triangle, a destination address (DA), a source address (SA), and a length. , LLC data, pad, frame check sequence (FC3
).

As shown in FIG. 3, each of the Ethernet interfaces 24 to 26 includes an Ethernet transceiver circuit 30 that detects collisions on the transmission line 23 and converts transmitted and received data into an Ethernet standard signal, and a Manchester The serial interface adapter 31 converts the data into a code and supplies it to the Ethernet transceiver circuit 30, and also decodes the data from the Ethernet transceiver circuit 30 and outputs it as serial data from a terminal 34.

The Ethernet interface 25 is connected to the terminal 61 via the AUI interface 40.

DA detection units 41.42 connected to the Ethernet interface 24.26 and the AUl interface 40, respectively
．． Each of 43 has the configuration shown in FIG. In the figure, terminal 4
5 receives serial data, and after detecting the frame start delimiter (SFD) shown in FIG. 3, the SFD detector 46 operates the 48-decimal counter 47, and the count value of this counter 47 becomes "48". In the meantime, the 48-bit destination address DA coming from the terminal 45 is stored in the buffer 48. This destination address DA is output from terminal 49.

D connected to Ethernet interface 24.26
Each of the A detection units 51 and 52 has a configuration shown in FIG. In the figure, serial data is input to the terminal 53, and the SFD voltage detector 54 is connected to the frame start delimiter (SFD
) after detecting the cascaded 48-decimal counter 55,5
6 is activated, and the count value of this counter 56 becomes "48".
”, the 48-bit source address SA coming from the terminal 45 is stored in the buffer 57.

This source address SA is output from terminal 58.

The address of the terminal 61 connected to this transceiver is stored in the own terminal address register 6o. The comparison circuit 62 compares the destination address detected by the DA detection unit 42 and the address from the own terminal address register 6°, and
The magnitude relationship between the two is supplied to the switch control section 63.

Each of the comparison circuits 65 and 66 has a configuration shown in FIG. In the same figure, terminals 70 and 71 each correspond to own terminal address register 6.
The address from 0 and the destination address from the DA detection units 41 and 43 are respectively input and compared at a comparison 72, and the comparison result is supplied from a terminal 73 to the switch control unit 63. If the comparison result is a match, the comparator 74 compares the source address from the SA detection unit 51.
6 notifies the switch control unit 63.

Further, the terminal 77 is notified of the connection state of the own terminal by the switch control unit 63, and the comparison circuit 65 (or 66) performs transmission and reception between the own terminal and the terminal connected to the transmission path 20a (or 20b). If the destination address is equal to or smaller (or larger) than the own terminal address, the terminal 78
Instructs the collision generation section 80 (or 81) to generate a collision.

Collision generating parts 80 and 81 are comparator circuits 65 and 66, respectively.
When each instruction is received, a collision occurs and the transmission lines 20a and 2 are connected via the Ethernet interfaces 24 and 26, respectively.
Send to each 0b.

Note that when the transceiver shown in FIG. 1 configures the bus-type LAN shown in FIG.
10b, 10f, IOc.

The addresses of each terminal are set so that the address value becomes smaller in the order of 11g, 10d, and 10b.

As shown in FIG. 7, the switch control unit 63 controls the comparator circuits 62.6 in an idle state in which the own terminal is not transmitting or receiving data.
5.66 (ignoring the respective comparison results (N0NE)), turn on switches SWI and SW2, turn off switches SW3 and SW4, and monitor data on transmission lines 20a and 20b.

In the transmission state, the comparison circuit 62 determines the destination address DA.
is greater than the own terminal address (indicated by "self-AJ" in the figure), switches SWI and SW4 are turned on, and switches SW2 .
SW3 is turned off, and when the destination address DA is smaller than the own terminal address, switches SWI and SW4 are turned off, and switches SW2 and SW3 are turned on. As a result, transmission line 2
0a20b is disassembled, and the own terminal or the transmission line 20a (or 2
0b), the other transmission path 20b
(or 20a) enables data transmission between terminals connected to each other.

In the receiving state, the comparison circuit 65. Or, if the destination address DA is larger or smaller than the own terminal address in 66, the switch SW1. SW2 on, switch SW3.3W
4 is off. In the comparison circuit 65, the destination address D
A matches the own terminal address, and the source address SA
is greater than the destination address DA, switch SW1.
SW4 is turned on and switch SE2.3W3 is turned off.

In the comparison circuit 66, the destination address DA matches the own terminal address, and the source address SA matches the destination address D.
If it is larger than A, switch SWI.

Turn off SW4, switch SW2. Turn on SW3.

In this way, when the destination address matches the own terminal address, the transmission lines 20a and 20b are divided 1, and even if the own terminal is receiving data from the transmission line 20a (or 20b), the other transmission line 20b (or 20a) enables data transmission between terminals connected to each other.

In this way, when one's own terminal is transmitting and receiving, the other terminal is on the transmission path 20a on both sides.

Comparison circuit 62.65°66 determines whether it is either 20b or
According to the comparison result, the switch control unit 63
switches the switches SWI to SW4 to divide the transmission lines on both sides, and terminate the transmission line on the other side that is not connected to the other party's terminal. Therefore, the transmission path on the other side can perform data transmission with another terminal, improving the efficiency of using the transmission path.

〔Effect of the invention〕

As described above, according to the bus-type LAN transceiver of the present invention, the transmission path can be divided and data can be sent from different terminals, thereby improving the usage efficiency of the transmission path, which is extremely useful in practice. .

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the transceiver of the present invention, Fig. 2 is a diagram showing the frame format of transmission data, Fig. 3 is a block diagram of the Ethernet interface, Fig. 4 is a block diagram of the DA detection section, FIG. 5 is a block diagram of the SA detection section, FIG. 6 is a block diagram of the comparison circuit, FIG. 7 is a diagram showing control of the switch control section, and FIG. 8 is a system configuration diagram of an example of a bus type LAN. In the figure, 20a and 20b are transmission lines, 23 is an internal transmission line, 24 to 26 are Ethernet interfaces, and 41 to 43
51.521 is a DA detection unit, 51.521 is a tSA detection unit, 60 is an own terminal address register, 6I is a terminal, 62.65.66 is a comparison circuit, 63 is a switch control unit, and SWI to SW4 are switches. Patent agent Fujitsu Ltd.

Claims (1)

[Claims] In a bus-type LAN transceiver that connects a terminal to the transmission path in a bus-type LAN in which a terminal that performs transmission occupies the transmission path, the transmission path (20a, 20b) connected on both sides is connected or The dividing switch means (SW1 to SW4) and the transmission line (20a, 2
0b) Comparison means (62, 65, 66) for determining which side of the terminal (62, 65, 66) the destination address or source address in the transmitted/received data is compared with the address of the own terminal (61).
And, based on the comparison results of the comparing means (62, 65, 66), the transmission line on one side to which the terminal of the other party which is transmitting and receiving from the own terminal (61) is connected and the transmission line on the other side are determined. the switch means (
1. A bus-type LAN transceiver comprising switch control means (63) for controlling switching of SW1 to SW4.