JP2655786B2 - LAN equipment of CSMA / CD 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 CSMA / CD system LAN device, and is used for a LAN using a twisted pair line.

[0002]

2. Description of the Related Art In a conventional star-type twisted pair LAN, a multi-port repeater is indispensable for constructing a network, and furthermore, the multi-port repeater causes a signal delay every time a signal passes, so that one multi-port repeater is required. The number of stages that can be cascaded is limited.

[0003]

In a conventional twisted pair LAN device, a signal delay occurs each time a signal passes,
Since collisions could not be detected simultaneously by each device, it was not possible to connect any number of LAN devices in series.

The present invention has been made in view of the above points, and an object of the present invention is to significantly reduce a signal delay caused by passing through a LAN device, thereby reducing each L signal.
Enables simultaneous detection of signal collisions in AN equipment,
An object of the present invention is to make it possible to connect a number of / CD LAN devices in series.

[0005]

According to the LAN device of the present invention, in order to solve the above-mentioned problems, as shown in FIGS. 1 and 2, in a LAN device in a CSMA / CD system LAN system, First and second twisted pair ports 1a and 1b, and first and second MAU function units 4 for realizing an MAU function conforming to the IEEE802.3 standard
a, 4b and the first and second MAU function units 4a, 4b to generate a jam signal conforming to the IEEE802.3 standard upon detection of a collision, except for the first and second twisted pair ports 1a, 1b A control circuit 3 having a function of outputting a control signal 9 when a reception signal is detected at the third port 2 of the first and second twisted pair ports 1a, 1
b transmission signal line Tx and first and second MAU function units 4
a, 4b, when the control circuit 3 detects a collision, or when the first and second twisted pair ports 1a,
1b, the first and second MAU function units 4a, 4b are connected to the transmission signal lines Tx of the first and second twisted pair ports 1a, 1b.
When the collision or the reception signal of the third port 2 is not detected, the transmission signal lines Tx of the first and second twisted pair ports 1a and 1b are connected.
And the first and second selector function units 6 which are directly connected to the reception signal lines Rx of the second and first twisted pair ports 1b and 1a.
a, 6b.

Here, the third port 2 is an AUI port connected to the DTE, and converts a voltage supplied from the AUI port into a constant voltage and supplies it to each unit.
When the power supply voltage is not supplied, the transmission signal lines T of the first and second twisted pair ports 1a and 1b are provided.
x is connected to the reception signal lines Rx of the second and first twisted pair ports 1b and 1a, respectively, and when the power supply voltage is supplied, the first and second twisted pair ports 1b and 1a are connected.
It is preferable to include first and second relay circuit sections 7a and 7b for connecting the transmission signal lines Tx of a and 1b to the first and second selector function sections 6a and 6b, respectively.

Further, as shown in FIGS. 3 and 4, CSM
NIU board 1 in A / CD LAN system
4, the first and second twisted pair ports 1a,
1b and NIU functional block 1 connected to DTE 11
3, the first and second MAU function units 4a and 4b for realizing the MAU function conforming to the IEEE 802.3 standard, and the first and second MAU function units 4a and 4b. A control circuit 3 having a function of generating a jam signal conforming to the .3 standard and outputting a control signal when the NIU function block 13 detects a received signal from the DTE 11, and a first and a second twisted pair port 1a , 1b and the first and second MAs.
Between the U function units 4a and 4b, when the control circuit 3 detects a collision, or when the NIU function block 13
When detecting the reception signal from E11, the first and second
When the signals output from the first and second MAU function units 4a and 4b are connected to the transmission signal lines Tx of the twisted pair ports 1a and 1b, respectively, when the collision or the reception signal from the DTE 11 is not detected, the first And first and second selector function units 6a and 6b that directly connect the transmission signal lines Tx of the second and first twisted pair ports 1a and 1b to the reception signal lines Rx of the second and first twisted pair ports 1a and 1b. Is not supplied, the transmission signal lines Tx of the first and second twisted pair ports 1a and 1b are connected to the reception signal lines Rx of the second and first twisted pair ports 1b and 1a.
And when the power supply voltage is being supplied, the transmission signal lines Tx of the first and second twisted pair ports 1a and 1b are connected to the first and second selector function units 6a and 6b.
b respectively connected to the first and second relay circuit portions 7
a, 7b are provided.

Further, as shown in FIG. 5 and FIG.
In the multi-port repeater 17 in the LAN system using the MA / CD system, two ports 1a and 1b among three or more twisted pair ports are used as cascade connection ports, and a repeater function and an MAU function conforming to IEEE802.3 are performed. A control circuit 15 having a function of outputting a control signal when a reception signal is detected at a port 16 other than the cascade connection ports 1a and 1b; When a received signal is detected at the port 16 other than the connection port,
When the transmission signal lines Tx of the first and second twisted pair ports 1a and 1b are connected to the control circuit 15 and no reception signal is detected at the port 16 other than the collision or cascade connection, the first and second twisted pair ports 1a and 1b are connected. Twisted pair port 1a, 1
b and the first and second transmission signal lines Tx directly connected to the reception signal lines Rx of the second and first twisted pair ports 1b and 1a.
Selector function units 6a and 6b.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a LAN using the CSMA / CD system.
In the device, a bypass path is provided to directly connect the reception signal lines of the two twisted pair ports to the transmission signal line of the other port without passing through the MAU function unit.
The signal delay caused by the passage through the AN device can be greatly reduced. When a signal collision is detected, or when a received signal is detected at an AUI port other than two twisted pair ports, an NIU functional block, or another twisted pair port, the selector function unit replaces the signal on the bypass path. , And the signal from the MAU function unit is supplied to the transmission signal line of each twisted pair port, so that the function as a normal LAN device can be maintained.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIGS. This embodiment relates to a multiport MA
This is an example applied to U10, and has two twisted pair ports 1a and 1b and one AUI port 2. The power of the multi-port MAU 10 is supplied from the DTE 11 via the AUI port 2, converted to a constant voltage by the constant voltage circuit 8, and supplied to each unit. The received signal Rx input from the twisted pair ports 1a and 1b is divided into two, one of which is the MAU function unit 4a or 4 for the twisted pair signal.
b, and is input to the control circuit 3, and the MAU for the AUI signal
AUI port 2 via function unit 5 and DTE 11
Is output to The other is input to the selector function units 6b and 6a and the relay circuit units 7b and 7a without passing through the control circuit 3 and the MAU function units 4a and 4b. Here, DTE1
1 is in the OFF state, the relay circuits 7a, 7b
Outputs the received signal Rx as it is as the transmitted signal Tx. When the power is ON, the relay circuit units 7a and 7b output the signals from the selector function units 6a and 6b as the transmission signal Tx without selecting the reception signal Rx.

The selector function units 6a and 6b are provided with the control circuit 3
Is switched by the control signal 9 when the input signal Do from the AUI port 2 is detected by the
The signal o is output to the two twisted pair ports 1a and 1b as a transmission signal Tx via the MAU function unit 5 and the control circuit 3, and then via the MAU function units 4a and 4b, the selector function units 6a and 6b, and the relay circuit units 7a and 7b. You. Also, three MAs
When a collision is detected in at least one of the U function units 4a, 4b, and 5, the selector signal unit 6 is switched by the control signal 9, and a jam signal is generated by the control circuit 3, and the jam signal is converted to the IEEE 802.3 standard. Output from the two twisted pair ports 1a and 1b. Each MAU
The function units 4a, 4b, and 5 fulfill the functions of the MAU specified in IEEE802.3.

[0012]

[Table 1]

Table 1 shows the function of each part and the signals flowing according to the state of the first embodiment. TP means the twisted pair ports 1a and 1b. When the power is off, the relay circuits 7a and 7b are directly connected to the twisted pair ports 1a and 1b, and the reception signal Rx is output as the transmission signal Tx without delay. When the power is turned on, the relay circuit units 7a, 7
b designates the twisted pair ports 1a and 1b as selector function units 6
a, 6b. Selector function units 6a, 6b
Normally, since the twisted pair ports 1a, 1b are connected to the relay circuit units 7b, 7a, the reception signal Rx is output as the transmission signal Tx without delay. AUI port 2
From the selector function units 6a, 6b
Connects the MAU function units 4a and 4b to the relay circuit units 7b and 7a.
To the input signal Do from the AUI port 2
It is output as a transmission signal Tx via the AU function units 4a and 4b. Also, when a collision of signals is detected, the selector function units 6a and 6b connect the MAU function units 4a and 4b to the relay circuit units 7a and 7b, so that the jam signal from the control circuit 3 receives the jam signal from the MAU function unit. The signal is output as a transmission signal Tx via 4a and 4b.

FIG. 2 shows an example of a network configuration using the multiport MAU 10 having the above configuration. In the figure, reference numeral 12 denotes a twisted pair cable. Multiport MAU of the present invention
10 is connected to the DTE 11 directly or via an AUI cable, so that a bus type network topology that does not require a multiport repeater completely different from the conventional star type topology using a multiport repeater and is easy to add and move is provided. Can be formed.

A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows an example in which the present invention is applied to a NIU (network interface unit) board 14, which has two twisted pair ports 1a and 1b. The first between the two twisted pair ports 1a, 1b
Control circuit 3 having functions shown in the embodiment, MAU function unit 4
a, 4b, selector function units 6a, 6b, relay circuit unit 7
a and 7b are provided. The received signal Rx input from the twisted pair ports 1a and 1b is divided into three, and one is MAU
Input to the control circuit 3 via the function units 4a and 4b,
It is output to the terminal via the function block 13. The other two
The received signal Rx is transmitted to the control circuit 3, the MAU function unit 4a,
The signal is input to the selector function units 6b and 6a and the relay circuit units 7b and 7a without passing through the relay circuit 4b. Here, if the power of the DTE 11 (that is, the NIU board 14) is off,
The relay circuit units 7a and 7b output the reception signal Rx as it is as the transmission signal Tx. When the power is ON, the relay circuit units 7a and 7b do not select the reception signal Rx, and output the signals from the selector function units 6a and 6b as the transmission signal Tx. The selector function units 6a and 6b are switched by the control signal 9 when a signal from the terminal is detected by the control circuit 3, and the signal from the terminal is transmitted to the MAU function unit 4a and 4b via the control circuit 3. The transmission signal Tx is output to the two twisted pair ports 1a and 1b via the selector function units 6a and 6b and the relay circuit units 7a and 7b. Also, one of the two MAU function units 4a and 4b
Even if any collision is detected, the selector signals 6a and 6b are switched by the control signal 9, and the control circuit 3 generates a jam signal.
2 twisted pair ports 1a,
1b.

FIG. 4 shows an example of a network configuration using the NIU board 14. By using the NIU board 14 of the present invention, the DTE 11
A simple and inexpensive network that can be interconnected with only 2 can be configured.

A third embodiment of the present invention will be described with reference to FIGS. FIG. 5 shows a multiport repeater 1 according to this embodiment.
7 is applied to a normal twisted pair port 16
Separately, two twisted pair ports 1a and 1b for cascade connection are provided, and the selector function units 6a and 6b having the function described in the first embodiment are provided between the ports 1a and 1b.
It has. The control circuit 15 has the MAU function and the repeater function of each port, and the function of the control circuit 3 shown in the first embodiment. The selector function units 6a and 6b are usually
Signals from the cascade connection twisted pair ports 1a and 1b are set to be output, and signals from the cascade connection twisted pair ports 1a and 1b are transmitted to the other cascade connection twisted pair ports 1b and 1a. At the same time, the same signal is output to each twisted pair port 16 via the control circuit 15 having a repeater function. When a signal is input to one of the twisted pair ports 16, a control signal 9 is generated by the control circuit 15 having a repeater function, and the selector signal 6 is generated by the control signal 9.
a and 6b are switched, and the repeated signal is output to all twisted pair ports 1a, 1b and 16. Also, when a collision occurs at any port, the selector function units 6a and 6b are switched, and the jam signal is transmitted from the control circuit 15 to all the ports according to the IEEE802.3 standard.

FIG. 6 shows a network configuration example using the multiport repeater 17 having the above configuration. In the figure, reference numeral 12 denotes a twisted pair cable. By using the multiport repeater 17 of the present invention, the signal delay of each repeater at the time of cascade connection is greatly reduced, so that the range in which collisions can be detected is simultaneously widened and the number of stages of cascade connection can be greatly increased. it can.

[0019]

According to the first or second aspect of the present invention, C
In SMA / CD twisted pair line LAN, 2
If no signal collision is detected in a LAN device with one twisted pair port and one AUI port, or
When the reception signal from the I port is not detected, the transmission signal line of each twisted pair port is directly connected to the reception signal line of the other twisted pair port, so that the signal delay caused by passing through the LAN device can be greatly reduced. Can,
In addition, unlike the conventional star-type network topology centered on multi-port repeaters, it is possible to construct a bus-type network that is cheaper, requires less wiring, and can be easily expanded and moved. is there.

According to the third aspect of the present invention, CSMA /
In a CD twisted pair line LAN, an N having two twisted pair ports and one NIU functional block
When no signal collision is detected on the IU board or when NI
When the reception signal from the DTE connected to the U function block is not detected, the transmission signal line of each twisted pair port is directly connected to the reception signal line of the other twisted pair port, so that the signal delay due to the passage of the LAN device is reduced. It can be significantly reduced, and it is inexpensive, completely different from the conventional star-type network topology centered on multiport repeaters, and can save wiring.
There is an effect that a bus-type network that can be easily moved can be constructed.

According to the fourth aspect of the present invention, CSMA /
In a CD twisted pair line LAN, a multiport repeater having three or more twisted pair ports,
The two ports are used as cascade connection ports, and when no signal collision is detected or when a reception signal from a port other than the cascade connection is not detected, the transmission signal line of each twisted pair port is connected to the reception signal of the other twisted pair port. Directly connected to the line, the signal delay when passing through a multi-port repeater can be greatly reduced, and the effect of being able to dramatically increase the number of stages of cascade connection, which was conventionally limited, is greatly increased. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a multi-port MAU using the present invention.

FIG. 2 is a schematic configuration diagram showing a configuration example of a network according to the present invention.

FIG. 3 is a block diagram showing a configuration of a NIU board using the present invention.

FIG. 4 is a schematic configuration diagram showing another configuration example of the network according to the present invention.

FIG. 5 is a block diagram showing a configuration of a multiport repeater using the present invention.

FIG. 6 is a schematic configuration diagram showing another configuration example of the network according to the present invention.

[Explanation of symbols]

 1a, 1b Twisted pair port 2 AUI port 3 Control circuit 4a, 4b MAU function unit for twisted pair signal 5a, 5b MAU function unit for AUI signal 6a, 6b Selector function unit 7a, 7b Relay circuit unit 8 Constant voltage circuit 9 Control signal 10 Multi Port MAU

Claims (4)

(57) [Claims] 1. A LAN device in a CSMA / CD system LAN system, comprising: a first and a second twisted pair port; and a MA conforming to the IEEE 802.3 standard.
A first and a second MAU function unit for realizing the U function;
And the second MAU function unit, and when a collision is detected,
Generating a jam signal conforming to the EEE802.3 standard,
A control circuit having a function of outputting a control signal when a reception signal is detected at a third port other than the first and second twisted pair ports; a transmission signal line of the first and second twisted pair ports; Interposed between the second MAU function units, when the control circuit detects a collision, or when a reception signal is detected at a third port other than the first and second twisted pair ports, The signals output from the first and second MAU function units are respectively connected to the transmission signal lines of the second twisted pair port, and when the collision or the reception signal of the third port is not detected, the first and second MAU function units are connected. A first and second selector function unit that directly connects a transmission signal line of the twisted pair port to a reception signal line of the second and first twisted pair ports.
MA / CD LAN equipment. 2. A third port connected to a DTE
A UI port, comprising a constant voltage circuit that converts a voltage supplied from the AUI port to a constant voltage and supplies the voltage to each unit;
When the power supply voltage is not supplied, the transmission signal lines of the first and second twisted pair ports are connected to the reception signal lines of the second and first twisted pair ports, respectively. 2. The CSMA / CD system according to claim 1, further comprising first and second relay circuit units for connecting transmission signal lines of a second and a second twisted pair port to the first and second selector function units, respectively. LAN equipment. 3. An NIU board in a CSMA / CD LAN system, wherein first and second twisted pair ports, an NIU function block connected to a DTE, and a MAU function compliant with the IEEE 802.3 standard are realized. First and second MAU function units, and first and second MAU function units
Connected to the MAU function unit of IEEE 8
A control circuit having a function of generating a jam signal conforming to the 22.3 standard and outputting a control signal when the NIU function block detects a reception signal from the DTE, and transmitting the control signal from the first and second twisted pair ports Signal line and first and second
When the control circuit detects a collision or when the NIU function block detects a reception signal from the DTE, the first and second twisted pair port transmission signal lines are connected to the transmission signal lines of the first and second twisted pair ports. Connect the signals output from the first and second MAU function units, respectively,
A first and a second selector function unit for directly connecting the transmission signal lines of the first and second twisted pair ports to the reception signal lines of the second and first twisted pair ports when detecting no reception signal from the power supply; When the voltage is not supplied, the transmission signal lines of the first and second twisted pair ports are connected to the reception signal lines of the second and first twisted pair ports, respectively.
First and second connecting the transmission signal lines of the second and second twisted pair ports to the first and second selector function units, respectively.
/ C characterized by comprising a relay circuit section of
D-type LAN equipment. 4. In a multi-port repeater in a LAN system using the CSMA / CD system, two ports among three or more twisted pair ports are used as cascade connection ports, and a repeater function conforming to the IEEE 802.3 standard is provided. A control circuit having a MAU function and having a function of outputting a control signal when a reception signal is detected at a port other than the cascade connection port; and When a reception signal is detected at a port, the transmission signal lines of the first and second twisted pair ports are connected to the control circuit, and when a reception signal is not detected at a port other than the collision or cascade connection, the first And the transmission signal line of the second twisted pair port is directly connected to the reception signal line of the second and first twisted pair port. L of the CSMA / CD system, comprising first and second selector function units.
AN equipment.