JPH03222542A - Line concentrator for network - Google Patents

Abstract

PURPOSE:To send a high priority data with high priority by giving an identifier in response to the degree of priority in advance to a data outputted from a terminal means. CONSTITUTION:An identifier in response to the degree of priority is given in advance to a data outputted from a terminal means 4. A data with high priority and a data with low priority are detected separately as a carrier by a 1st carrier detection means 52a and a 2nd carrier detection means 52b and a 1st collision detection means 53a and a 2nd collision detection means 53b detect collision separately between data with low priority and between data with high priority outputted from plural terminal means 4. Then a data with high priority is sent with priority by a control signal from a control means 58 and a data with low priority is stored tentatively in a buffer means 56 by controlling a switch means 57. Thus, the data with high priority is sent with high priority.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a network line concentrator, which is used for connecting a large number of terminal devices to a trunk line of a network at once.

[Conventional technology]

BACKGROUND ART Conventionally, a local area network (LAN) has been widely used for comprehensively communicating information within a premises. In particular, Ethernet-type private communication networks that comply with the IEEE802.3 standard are widely used. This Ethernet-type local area communication network has a lotus-type topology in which multiple terminals are connected to a two-wire transmission line such as a coaxial cable.
/CD (Carrier 5ense Mul
Tiple Access/Co11isionD
In this method, the source terminal first senses the state of the transmission line, confirms that no packets (data with addresses) are being sent on the transmission line, and then sends out its own packet. If there is a packet on the transmission line, it waits until that packet has been sent before sending out its own packet. It constantly senses the transmission line even while sending a packet, and if a signal different from the one it sent appears on the transmission line, it determines that the packet has been destroyed and starts retransmitting the packet.

C3MA that complies with such IEEE802.3 standards
/CD type LAN, as shown in Figure 2,
A transceiver means 2 is connected to the coaxial cable 1 which becomes the trunk line of the network, and the AUI (
The terminal means 4 is connected via the Access Unit Interface (Access Unit Interface) cable 3. The transceiver means 2 has a data transmission/reception function and a data collision detection function. On the other hand, when connecting a plurality of terminal means 4 to one transceiver means 2, a concentrator (concentrator) 5 called HU B is connected to the transceiver means 2 via the AUI cable 3, and a plurality of terminal means 4 are connected to the transceiver means 2 via the AUI cable 3. Terminal means 4 is connected. Multiple terminal means 4
A data collision between the lines is detected by collision detection means 53 provided in the line concentrator 5. That is, data transmitted from the terminal means 4 is input to the carrier detection means 52 via the input/output signal buffer means 51, and the carrier detection means 52 detects the carrier. The carrier detection signal outputted from the carrier detection means 52 is input to the collision detection means 53, and it is determined whether a carrier detection signal is also generated from another terminal means 4 at the same time. If no carrier detection signal is generated from another terminal means 4, the data from said terminal means 4 is transmitted to the transceiver means 2 via the input/output signal buffer means 54.

[Problem to be solved by the invention]

However, in the line concentrator 5 as described above, when a large amount of data is generated from a large number of connected terminal means 4, many collisions occur, and for example, data with high priority and data with low priority occur. There is a problem in that when there is a collision, data with a lower priority is transmitted first, making it difficult to send data with a higher priority.

The present invention has been made in view of the above points, and an object thereof is to provide a network concentrator that enables preferential transmission of high priority data.

(Means for Solving the Problems) A network line concentrator of the present invention includes input/output signal buffering means for buffering input/output signals from terminal means;
a signal identification means for identifying an identifier according to a high or low priority given in advance to the data sent from the terminal means, and distributing the data according to the identifier; A first carrier detection means for data with low priority and a second carrier detection means for data with high priority are provided, and an output of the first carrier detection means for each of the plurality of terminal means, The first collision detection means detects whether or not there is a collision between data of low priority, and the output of the second carrier detection means for each of the plurality of terminal means detects a collision between data of high priority. a second collision detection means for detecting whether or not there is a collision, a buffer means for temporarily storing low priority data, and selecting either high priority data or low priority data stored in the buffer. The apparatus is characterized by comprising a switch means, a control means for controlling the switch means by the output of the second collision detection means, and an input/output signal buffer means serving as a buffer for input/output signals from the outside. .

[Effect]

In the present invention, an identifier is assigned in advance to the data output from the terminal means according to the level of priority, and data with high priority and data with low priority are sent to the first carrier detection means and the second carrier detection means. Carrier detection is performed separately by
By the first collision detection means and the second collision detection means,
Collision detection is performed separately between low-priority data and high-priority data from multiple terminal means, and data with high priority is transmitted preferentially by a control signal from the control means. The switch means is controlled so that low-quality data is temporarily stored in the buffer means.

(Example) An example of the present invention will be described below based on the drawings.
1F is a bronc diagram showing an embodiment of the present invention. In the figure, the part surrounded by the dotted chain line is the line concentrator 5. 4 is a terminal means 4 consisting of a personal computer, a workstation, or the like. The data output from the terminal means 4 is given an identifier indicating the priority level in advance. 51.
54 is input/output signal buffer means for impedance conversion and waveform shaping.

Reference numeral 55 denotes a priority identification means, which identifies the priority using an identifier given to the data in advance, and sorts the data according to the high or low priority.

52a and 52b are a first carrier detection means and a second carrier detection means that detect the presence or absence of a data carrier, and the detection results are respectively transmitted to a first collision detection means 53a, which will be described later.
and sends it to the second collision detection means 53b. Data with a low priority is input to the first carrier detection means 52a, and data with a high priority is manually input to the second carrier detection means 52b.

The part surrounded by the broken line in Figure 1 has the same configuration,
Carriers from other terminal means 4 are detected in the same manner, and the detection results are sent to collision detection means 53a and 53b, respectively.

Reference numerals 53a and 53b denote a first collision detection means and a second collision detection means for detecting a collision of data from a plurality of terminal means 4, and each terminal means 4 detects a collision based on the carriers from the plurality of terminal means 4. It is detected whether there are attempts to send data at the same time, and if a collision occurs, a collision detection signal is sent to each terminal means 4 and transceiver means 2. Data with low priority is input to the first collision detection means 53a, and collisions between data with low priority are detected, data with high priority is input to the second collision detection means 53b,
Collisions between high-priority data are detected.

Reference numeral 56 denotes Hanwha means, which temporarily stores data output from the first collision detection means 53a, and stores the data outputted from the first collision detection means 53a.
7 is connected to the buffer means 56 side, the stored data is output.

Reference numeral 57 denotes a switch means for switching which of the data from the first and second collision detection means 53a, 53b is to be transmitted to the input/output signal buffer means 54. This switching is performed by a control signal from a control means 58, which will be described later.

A control means 58 outputs a control signal for switching the switch means 57 in response to a signal from the second collision detection means 53b. That is, normally the switch of the switch means 57 is connected to the buffer means 56 side, but when data with a high priority passes through the second collision detection means 53b, a control signal is output from the control means 58, and the switch means 5
The switch No. 7 is switched to the second collision detection means 53'b side. The high priority data is then transmitted to the transceiver means 2 via the input/output signal buffer means 54. When this transmission is completed, the switch means 57 is switched to the buffer means 56 side by a control signal from the control means 58.

Note that 1 is the coaxial cable that serves as the trunk line of the network, and 2
3 is a transceiver means having a data transmission/reception function and a data collision detection function; 3 is an AU1 cable for connecting the transceiver means 2 and the terminal means 4; The AUI cable uses 2 wires for transmission, 2 wires for reception, 2 wires for collision detection, and 2 wires for power, for a total of 8 wires. Transceiver means 2
Since the collision detection signal (a signal that detects a collision between the transceiver means 2) is separately included in the signal input to the line concentrator 5 from the transceiver means 2, there is no need to perform carrier detection. The collision detection signal is sent to the first and second collision detection means 53a.

53b and sends it out to each terminal means 4.

Next, the operation of this embodiment will be explained. All data includes
Identifiers are assigned in advance depending on the level of priority. Further, the connection state of the switch means 57 is such that the buffer means 56 and the input/output signal buffer means 54 are normally connected.

Data transmitted from the terminal means 4 is inputted to the signal identification means 55 via the input/output signal buffer means 51, and is identified by the identifier given to the data, and data with high priority is sent to the second carrier detection means. 52b, and low priority data is transmitted to the first carrier detection means 52a. first and second carrier detection means 52a,
At step 52, the presence or absence of a carrier is detected and sent to first and second collision detection means 53a and 53b. The first and second collision detection means 53a and 53b detect whether or not a collision has occurred between data from a plurality of terminal means 4, and if a collision has occurred, each terminal means 4 and the transceiver A collision detection signal is sent to the means 2, and if no collision has occurred, the data is taken in and sent to the subsequent stage. Furthermore, in the second collision detection means 53b, when the data is input, the second collision detection means 53b sends the data to the control means 58.
A signal indicating that data has been input is sent to the control means 58.
A control signal for switching the switch to the second collision detection means 53b is output to the switch means 57. As a result, data with a high priority is transmitted from the second collision detection means 53b to the transceiver means 2 via the switch means 57 and the input/output signal buffer means 54. Once the transmission of this high-priority data is finished,
The switch means 57 is activated by the control signal from the control means 5B.
is switched to the side of the sofa 56.

Data with a low priority is transmitted to the buffer means 56 via the first collision detection means 52a, and is temporarily stored within the buffer means 56. The data input to the buffer means 56 is transferred to the buffer means 57 when there is a request to send high priority data, that is, when there is no high priority data in the first collision detection means 53b. 56 side, the signals are sequentially transmitted to the transceiver means 2 via the switch means 57 and the input/output signal buffer means 54. While transmitting high-priority data, until the transmission of that data is finished, that is,
It waits in the buffer 56 until the switch means 57 is switched by a control signal from the control means 58.

Also, during the transmission of low-priority data, other terminal means 4
When data with high priority is generated, the switch means 5
By switching 7, the transmission of data with low priority is temporarily interrupted, and data with high priority is transmitted preferentially.

According to this embodiment, data output from the terminal means 4 is given an identifier depending on its priority, and data with a high priority is transmitted preferentially. Also, data collision detection involves detecting collisions between high-priority data and between low-priority data, so for example, if low-priority data and high-priority data collide. Therefore, data with a low priority is not transmitted first, and data with a high priority cannot be transmitted because of the data with a low priority.

〔Effect of the invention〕

As described above, according to the network concentrator of the present invention, an identifier is assigned in advance to the data output from the terminal means according to the level of priority, and data with high priority and data with low priority are assigned to the data output from the terminal means. The first carrier detecting means and the second carrier detecting means perform carrier detection separately, and the first collision detecting means and the second collision detecting means distinguish between data of low priority and data of high priority from a plurality of terminal means. Collision detection is performed separately between high-priority data, data with a high priority is transmitted preferentially by a control signal from a control means, and data with a low priority is temporarily stored in a buffer means. By controlling the switching means and stages, we were able to provide a network concentrator that enables preferential transmission of high-priority data.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. 1-Coaxial cable 2-) Transceiver means 3-AU
■Cable 4 - Terminal means 5 - Line concentrator 51.54 - Human output signal huffer means 52a - First carrier detection means 52b - Second carrier detection means 53a - First collision detection means 53b - Second collision detection means

Claims (1)

[Claims] (1) Identify the input/output signal buffer means that serves as a buffer for input/output signals from the terminal means and the identifier according to the priority given in advance to the data sent from the terminal means, and use the identifier to process the data. A signal identifying means for distributing, a first carrier detecting means for low priority data and a second carrier for high priority data provided for each data distributed according to high or low priority. a first collision detection means for detecting whether or not there is a collision between low-priority data based on the output of the first carrier detection means for each of the plurality of terminal means; a second collision detection means for detecting whether or not there is a collision between high priority data based on the output of the second carrier detection means for each; a buffer means for temporarily storing low priority data; switch means for selecting either high-priority data or low-priority data stored in a buffer; control means for controlling the switch means based on the output of the second collision detection means; and input/output from the outside. 1. A network line concentrator comprising input/output signal buffer means serving as a signal buffer.