KR0179282B1 - Apparatus for detecting data collision and method thereof - Google Patents

Abstract

The present invention relates to data communications, and to provide a data collision detection apparatus and method suitable for detecting data collisions that may occur in full-duplex data communications.

The data collision detection apparatus of the present invention for this purpose is a receiving end address separating unit for separating the address of the receiving end from the data transmitted from the transmitting end, a transmitting end address separating unit for separating the address of the transmitting end from the data transmitted from the transmitting end, and the receiving end address A memory unit for storing a receiving end address output from the separating unit, a data end detecting unit for detecting the end of the data transmitted from the transmitting end and clearing the data in the memory, and a memory for controlling the order of data writing and reading of the memory unit A control unit, a first comparing unit comparing the receiving end address stored in the memory with a receiving end address; a jamming pattern signal generating unit generating a jamming pattern signal according to an output signal of the first comparing unit in case of data collision; and the transmitting end address. Comparing the data stored in the memory unit with the data stored in the memory unit; It is configured to include the second comparison unit for determining whether to output the Ming pattern signal.

Description

Data collision detection device and method

The present invention relates to data communication, and more particularly, to an apparatus and method for detecting data collisions that may occur during full-duplex data transmission.

In general, how to transfer information between data terminal apparatuses in time is called a totalization method, and there are three types such as simplex, half duplex, and full duplex.

One-way communication means communication in one direction only, and communication in the opposite direction is impossible. Half-duplex communication allows communication in opposite directions but does not overlap in time. It is not possible to communicate in the opposite direction after it is finished, and full-duplex communication is similar to half-duplex communication, but in the case of overlapping in time, that is, a method of transmitting and receiving at the same time.

According to these various communication methods, the error of information transmission and the time efficiency, that is, how fast the communication is determined.

Since the code used for data communication consists of a binary signal with the minimum number of bits required, there is no redundancy, so even if the binary signal constituting the code is wrong during transmission, the receiving side is different. Know by sign. The fact that one bit is not wrong in a transmission system cannot be expected, and therefore, it has become an important problem in countering transmission errors in a data communication system.

In the case of unidirectional transmission, it is impossible for the sender to know whether or not it has been received without error. Therefore, the transmission reliability is improved by using a sufficiently high error correction code or transmitting the same information several times from the beginning. However, the transmission efficiency is greatly reduced.

In the case of half- and full-duplex, since information from the opposite direction can be obtained, the information to be transmitted is divided into blocks of any size, and a relatively simple error detection code is added to the block and transmitted. The countermeasures can be taken, such as resending only the blocks that are found to contain errors. Therefore, the reliability of the transmission can be improved and the efficiency can be improved. The highest transmission efficiency is obtained because information can be obtained and large amounts of data can be transmitted in both directions.

Referring to the accompanying drawings, a conventional data collision detection method will be described below.

FIG. 1 is a diagram showing the minimum unit of a network in which data transmission medium is TP (Twist Pair).

As shown in FIG. 1, since a HUB necessary for transmitting data between a plurality of terminal devices simply repeats data, when a data is transmitted from one terminal device, the HUB is transmitted from the terminal device. Send data to all other terminal devices.

Therefore, when each terminal device is transmitting data, if data exists on the receiving side, it recognizes that the data is a collision.

2 is a diagram illustrating a switching HUB using a conventional full-duplex method.

The configuration of the system according to FIG. 2 is the same as that of FIG. 1, but each terminal device has a function of simultaneously performing transmission and reception, so that a collision detection method such as a half-duplex method cannot detect a collision. There is no concept of conflict.

3 shows the truth table according to FIG.

As shown in FIG. 3, the full-duplex scheme has a higher data transfer rate than the half-duplex scheme, and thus the bandwidth of the entire data transmission network is considerably high.

However, when two terminal devices simultaneously transmit data to the same terminal device, the data may cause a collision, and the terminal device may not prepare for this.

Therefore, when a collision occurs, the receiving axis detects the loss of received data and requests retransmission.

In this case, retransmission means transmitting data requesting retransmission to a receiving end that received the collided data.

At this time, the data that means retransmission may also cause data collision, so the entire network may be in a bad cycle of retransmission.

For example, when the terminal device A transmits data to send the data to the terminal device B, the switching HUB analyzes the data transmitted by the terminal device A and finds out that the data is the data to be transmitted to the terminal device B. The data transmitted from the device A is transmitted to the terminal device B.

At this time, if the terminal device C simultaneously transmits data to the terminal device A, the switching HUB receives the data transmitted from the terminal device C and transmits the data to the terminal device A.

In contrast, in the case of the half-duplex method, when the terminal device A transmits data from the terminal device C to the terminal device A while transmitting data to the terminal device B, a collision occurs between the data.

Therefore, since each terminal device transmits data again, the data transmission bandwidth of the entire network is reduced.

The conventional data collision detection method as described above has the following problems.

That is, in case of full-duplex method, if the receiver requests retransmission when data collision occurs, the efficiency of the network becomes low, and if the retransmission request data collides again, the bad cycle of retransmission repeats and the network efficiency is reduced. Drops sharply.

The present invention has been made to solve the above problems, to provide a collision detection apparatus and method suitable for improving the efficiency of the network that can occur when data collision by enabling collision detection in a full-duplex switching HUB system The purpose is.

1 is a diagram showing a minimum unit of a network in which data transmission medium is TP (Twist Pair).

2 shows a switching HUB using a conventional full duplex scheme.

3 is a block diagram of a data collision detection apparatus of the present invention.

4 is a diagram illustrating a retransmission process of data after a data collision.

5 is a packet configuration diagram of the Ethernet method.

6 is a flowchart showing a data collision detection method of the present invention.

* Explanation of symbols for main parts of the drawings

31: DA separation unit 32: memory unit

33: first counter part 34: second counter part

35: SA separation unit 36: data end detection unit

37: first comparison 38: second comparison

39: jamming pattern generator 41: jamming pattern defector

42: back-off timer

The data collision detection apparatus of the present invention for achieving the above object is a receiver address separator for separating the address of the receiver from the data transmitted from the transmitter, and a transmitter address separator for separating the address of the transmitter from the data transmitted from the transmitter And a memory unit for storing the receiving end address outputted from the receiving end address separating unit, a data end detecting unit detecting the end of data transmitted from the transmitting end and clearing the data in the memory; A memory control unit for controlling an order, a first comparison unit for comparing a receiving end address stored in the memory and a receiving end address stored in the memory, and a jamming pattern signal generating unit generating a jamming pattern signal according to an output signal of the first comparing unit in case of data collision And data stored in the transmitter address separator and the memory. The data collision detection method of the present invention comprises the step of separating the address of the receiver from the data transmitted from the transmitter, storing the address of the receiver in the memory. Determining whether the data currently stored in the memory and the data to be stored are the same; if the result of the determination is not the same, the address of the receiving end is stored in the memory unit; Determining whether or not to receive, and if the other data is received, waiting for a predetermined time, otherwise outputting the jamming pattern signal to the transmitting end, and notifying the transmitting end of the collision of data in the switching HUB.

Hereinafter, an apparatus and method for detecting data collision according to the present invention will be described with reference to the accompanying drawings.

3 is a block diagram of a data collision detection apparatus of the present invention.

First, as shown in FIG. 3, a DA separating unit 31 for separating an address of a receiving end from data transmitted from a terminal device and N addresses for temporarily storing an address of a receiving end from data transmitted from the terminal device are shown. A memory unit 32 having a memory, a first counter unit 33 for determining an order of writing data into the memory unit 32, and a sequence for reading data stored in the memory unit 32; A second counter 34 to separate the SA separator 35 to separate the address of the transmitting end from the data transmitted from the terminal device, and a data end detector 36 to detect the end of the data transmitted from the terminal device. And a first comparator 37 for comparing the address of the receiver separated in the DA separator 31 with the address of the receiver currently stored in the memory 32, and separated from the SA separator 35. Sender's address and the sender's address currently stored in memory 32 And a second comparator 38 for comparing addresses, and a jamming pattern generator 39 for generating data having a value of all 32 bits when a data collision occurs.

Here, the jamming pattern generator 39 is connected to one side terminal of the AND gate 40 that logically computes the signal of which the output of the second comparator 38 is inverted and the output of the jamming pattern generator 39. .

The operation description of the data collision detection apparatus of the present invention configured as described above is as follows.

As shown in FIG. 3, the DA separator 31 separates only the address of the receiver from the packet data transmitted from the terminal device. The output terminal is connected to a six-byte memory section 32 having N addresses.

Therefore, the memory unit 32 stores the address of the receiving end separated by the DA separating unit 31.

In this case, the first comparator 37 compares the data output from the DA separator 31 with the data currently stored in the memory 32 to inform whether data collides with each other.

Here, the data stored in the memory unit 32 refers to the address of the terminal currently receiving the data.

If there is no such comparison process, another data is sent to the terminal receiving the current data, which causes a data collision.

Accordingly, the first comparator 37 may determine whether the address of the receiver currently receiving data and the address of the receiver output from the DA separator 31 are the same.

In this case, in order for the data stored in the memory 32 to point to the address of the terminal currently being received, all data stored in the memory 32 must be cleared after the reception of the data is completed.

The data end detection unit 36 is responsible for the clearing.

That is, the data end detection unit 36 detects the end of the data transmitted from the terminal device, and if the end of the data is detected, recognizes that data reception is completed and clears the data stored in the memory unit 32.

In this manner, the first counter unit 33 and the second counter unit 34 are responsible for determining the time point at which the data is stored or read in the memory unit 32.

In this case, when a data collision occurs as a result of the comparison of the first comparison unit 37, a collision signal indicating that a collision has occurred is output and simultaneously output to the jamming pattern generator 39.

In this case, when data collision occurs, the second comparator 38 determines when to output the data output from the jamming pattern generator 39 to the transmitting end of the terminal device.

This is because the data of the jamming pattern generator 39 generated at the time of the data collision must be sent to the transmitting end of the terminal device. Therefore, it is necessary to determine whether the transmitting end having the current collision has received the data.

That is, when a collision of data occurs, the second comparator 38 compares the address of the transmitter output from the SA separator 35 with the data value stored in the memory 32 so that the same data does not exist. If not, the output signal of the jamming pattern generator 39 is output to the transmitting end.

In other words, the jamming pattern generator 39 applies a signal to one terminal of the AND gate 40 connected to the jamming pattern generator 39 when the transmitting end of the current data collision is not receiving data. Logic operation is performed on the output signal of the jamming pattern generator 39 to output to the transmitting end.

Therefore, the switching HUB detects the collision of data and informs the collision signal of the terminal device which collided.

4 is a diagram illustrating a retransmission process of data after a data collision.

As shown in FIG. 4, a jamming pattern detector 41 for detecting data of all 32 bits is included, and a back-off timer 42 for preventing collision of data is included. .

Here, the jamming pattern detector 41 enables the back-off timer 42 when the jamming pattern is detected by the terminal device.

Therefore, the back-off timer 42 always retransmits the data after a random time since there is a possibility of re-collision of data when a delay of a certain length is achieved.

5 is a block diagram of an Ethernet packet.

That is, as shown in FIG. 5, the preamble bit (62 bit) and the start frame delimiter (SFD) inform the start of the frame. DA (Destination Address) represents the address of the receiver, and SA (Source Address) represents the address of the transmitter. It is divided into an area indicating the length of data to be transmitted, an area containing data to be transmitted, and an FCS (Frame Check Sequence) area used as a code for error detection.

6 is a flowchart showing a data collision detection method of the present invention.

In the data collision detection method of the present invention, as shown in FIG. 6, first, when data is transmitted from the data transmitting terminal device (101), only the address of the receiving terminal device receiving the data is separated (102) by the DA separating unit. .

Subsequently, the address of the receiving terminal is stored in the memory unit. Before the storing, the address of the receiving terminal device to be stored in the memory unit and the address of the receiving terminal device currently stored in the memory unit are compared (103).

As a result of the comparison, if the addresses are the same, a collision of data is detected and a collision signal is generated (104).

When a collision signal is generated, it is judged whether or not the transmitting terminal device which has transmitted the data is receiving other data (105). If the transmitting terminal device does not receive other data, it outputs a jamming pattern to the transmitting terminal (106).

Accordingly, the switching HUB detects the collision and notifies the transmitting terminal apparatus of the collision (107).

The transmitting terminal device then detects 108 the jamming pattern and then enables 109 the back-off timer.

After a predetermined time, the data is retransmitted (110). At this time, as described above, the address of the receiving terminal device currently stored in the memory unit is compared with the address of the receiving terminal device to be stored in the memory unit (103).

As described above, the data collision detection apparatus and method of the present invention have the following effects.

That is, in the full-duplex switching HUB system, it is possible to detect whether data collides, thereby improving the efficiency of a network that may occur during data collision.

Claims (5)

A receiver address separator for separating an address of a receiver from data transmitted from a transmitter, a transmitter address separator for separating an address of a transmitter from data transmitted from the transmitter, and a receiver address outputted from the receiver address separator A memory end, a data end detection unit for detecting end of data transmitted from the transmitting end and clearing the data in the memory, a memory control unit controlling the order of data writing and reading of the memory unit, a receiving end address stored in the memory; A first comparator for comparing a receiver address to be stored, a jamming pattern signal generator for generating a jamming pattern signal according to an output signal of the first comparator in case of a data collision, data of the transmitter address separator and data stored in the memory part Comparison and determining a second output of the jamming pattern signal; Data collision detection device comprising a unit. The apparatus of claim 1, wherein the memory controller is configured as a counter according to reading and writing. The apparatus of claim 1, wherein the data transmitted from the transmitter is transmitted in the form of a packet. Separating the address of the receiver from the data transmitted by the transmitter; determining whether the data currently stored in the memory and the data to be stored are identical before storing the address of the receiver in the memory; Storing data in the memory unit, otherwise generating a data collision signal, and determining whether other data is being received by the terminal that has transmitted the data, waiting for a predetermined time if other data is being received, or otherwise outputting a jamming pattern signal to the transmitting terminal. And informing the transmitting end of the collision of data in the switching HUB. 5. The method of claim 4, wherein the transmitting end detects a jamming pattern signal and enables a back-off timer when notifying the transmitting end of the collision in the switching HUB, and retransmitting data after a predetermined time. Data collision detection method characterized in that.