JPH04101532A - Transmission control system - Google Patents

Abstract

PURPOSE:To carry out realtime recognition of data transmission by intentionally making a sender sending a redundant field generate collision of the redundant field and making the sender inform a receiving side of the success of receiving the frame when the frame can be received at the receiving station side. CONSTITUTION:In an error judgement circuit 23, a frame check sequence calculated from a bit pattern covering a range from the first bit of a destination address field 31 to the last bit of a data field 34 is compared with the value of a frame check sequence field 35 transferred from a receiving circuit 21, as a result, if it is judged that they coincide with each other and there is no error, the error judgement circuit 23 informs a collision circuit 22 that there is no error. When the collision circuit 22 is informed that there is no error, the collision circuit 22 sends random data to a transmission line 20, and a transmission circuit 11 makes collision of the redundant field 36 of frame during sending the frame. When the collision occurs, a collision judgement circuit 12 judges that data has been correctly transmitted to a destination station.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a transmission control method, particularly a transmission control method for transmission confirmation in a local area network system [Prior Art] Conventionally, as a typical example of this type of network system,
Ethernet: DEC Corporation, USA
Trademark of IN Kiso Co., Ltd. and XERO Co., Ltd. Source: ALocal
Network Data Link Lay
er and PhysicaLayer 5pe
cifica tions), IEEE Standard 802
．． 3 (Source: CSMA/CD ACCESSMET
OD AND PHYSICAL LAY
ER5PECIFICATIONS) Local Area Network
rk is abbreviated as LAN. ) There is a system.

In these LAN systems, a plurality of stations each having a station address are connected to a common transmission path, and a preamble (Preamble) shown in FIG.
a synchronization code field called I e ) and a station address (DestinaLi) that specifies the destination station.

n Address: field (hereinafter referred to as DA) and station address (Source Add) indicating the source.
ress (hereinafter referred to as SA) field, a data field containing control information, and a frame check sequence (
FCS: Frame Check Seguen
ce) A frame consisting of fields is transmitted serially when the transmission path is empty.

If it is detected that a collision has occurred on the transmission path due to frame transmission from another station after transmission has started, the transmission is stopped, the transmission waits for a period of time determined by a random number, and then the transmission path is checked again for free space. The frame shown in FIG. 5 is transmitted.

After each station connected to the transmission path completes bit and character synchronization using the preamble, it compares the DA in the received frame with its own address, and if the frame matches, it will be processed without any FCS errors or collisions. Each station on the transmission path communicates with each other by taking in the frame as its own frame only when reception is completed correctly.

In such a LAN system, the method for confirming that the transmitted complaint has been correctly received by the destination station, regardless of reception error or transmission path failure, is based on the communication protocol established between each station, and the frame is The receiving station is D
This is realized by exchanging 'A and SA, and sending the frame shown in FIG. 6, in which a code indicating successful reception is set as control information, to the transmission path as a response frame.

[Problem to be solved by the invention]

The conventional transmission control method described above lacks a real-time system because it performs the transmission and reception of response frames, and furthermore, it requires a complicated communication protocol that takes into account recovery measures in the event that the response frame is not transmitted correctly. There is.

[Means to solve the problem]

The transmission control method of the present invention specifies whether each station is a plurality of stations having a station address, a station connected to a common transmission path and attempting to transmit, a synchronization code field, and a partner station address field that specifies the destination station. , the own station address field indicating the source, the data length field indicating the length of the data field containing control information, the data field containing control information, and the distance from the first bit of the destination station address field to the end of the data field. a frame check sequence field storing a frame check sequence determined from the bit pattern up to bits;
A frame consisting of a redundant field with a length that requires a transmission time more than twice the transmission delay time that occurs in the entire network is serially transmitted when the transmission path is empty, and the synchronization code field is being transmitted. If it is detected that a collision has occurred on the transmission path due to frame transmission by another station, the transmission is stopped, the transmission waits for a time determined by a random number, and then the transmission path is checked again to transmit the frame. After each station that transmits data and is connected to the transmission path completes synchronization using the synchronization code field of the frame, it compares the station address indicated in the partner station address field of the frame with its own address, and selects a frame that matches. The frame check sequence obtained from the bit pattern from the first bit of the partner station address field to the last bit of the data field is compared with the frame check sequence field of the frame, and if they match, In a transmission control method for an information processing device that includes a network system that captures the frame as a frame addressed to the local station, there is a frame check sequence error in the receiving circuit that extracts the frame addressed to the local station from the transmission path, and in the received frame. a collision circuit that intentionally causes a collision for the purpose of notifying the source station that normal reception has been completed during redundant field reception of the frame addressed to the local station; and a transmission circuit that transmits the frame to the transmission path. and a collision determination circuit that determines whether a collision has occurred while transmitting the redundant field of the frame, and if the destination station can correctly receive the frame, the source transmits the redundant field. Successful reception is notified by intentionally causing a collision during the transmission.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of the transmitting side of an information processing device showing an embodiment of the present invention, FIG. 2 is a block diagram of the receiving side, and FIG. 3 is a block diagram of the transmitting side of an information processing device showing an embodiment of the present invention. This is the format of the frame that will be displayed.

A transmitting circuit 11 connected to the transmission path 10 transmits the frame shown in FIG. 3 to the transmission path 10 after acquiring a transmission right based on IEEE standard 802.3 (see the section of the prior art). A receiving circuit 21 connected to a transmission path 20 common to the transmission path 10 extracts the frame shown in FIG. 3 from the transmission path 20, and if the destination station address field 31 of the frame matches the address of the own station, In parallel with the reception, the error determination circuit 23 sequentially reads the frame from the destination address field 31 to the source address field 32 .
Data Length Field 33 A data field 34 having the length indicated by the data length field 33 and a frame check sequence field 34 are transferred.

In the error determination circuit 23, the destination station address field 31
The frame check sequence calculated from the bit pattern from the first bit to the last bit of the data field 34 is compared with the value of the frame check sequence field 35 transferred from the receiving circuit 21, and it is determined that they match and there is no error. If it is determined that there is no error, the collision circuit 22 is notified.

When the collision circuit 22 is notified that there is no error, the transmission line 2
Send random data to 0.

As a result, in the transmission path 10 common to the transmission path 20, the transmitting circuit 10 uses the redundant field 36 of the frame shown in FIG.
A collision occurs during transmission.

In the collision determination circuit 12, if a collision occurs during transmission of the redundant field 36 of the frame shown in FIG. It is determined that the information has not been transmitted.

FIG. 4 shows the timing of a collision that occurs when transmitted data is correctly received by the information processing apparatus using the transmission control method of the present invention.

As shown in FIG. 4, if the transmitted data is correctly received by the destination station, a collision occurs in the redundancy field 56;
Transmission confirmation becomes possible.

〔Effect of the invention〕

As explained above, in the transmission control method of the present invention, if the destination station successfully receives the data correctly, the source station intentionally causes a collision during the redundant field transmission that continues to send valid data. By confirming the transmission,
Because transmission confirmation is completed at the time transmission is completed, transmission confirmation can be performed in real time compared to the conventional confirmation method by sending and receiving response frames, and there is no need for recovery measures when response frames are not transmitted correctly. This has the effect of simplifying the rules.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the transmitting side of an information processing device showing an embodiment of the present invention, FIG. 2 is a block diagram of the receiving side as well, and FIG. 3 is a block diagram of information exchange between information processing devices using the transmission control method of the present invention. FIG. 4 is a diagram showing the timing of a collision that occurs when transmitted data is correctly received in an information processing apparatus using the transmission control method of the present invention, and FIG. 5 shows a conventional example. Frame Format FIG. 6 shows the format of a conventional response frame. 10... Transmission line, 11... Collision determination circuit, 20...
- Transmission line, 21... Collision circuit, 22... Error determination circuit, 30... Preamble field, 31...
Destination station address field, 32... Source address field, 33... Data length field, 34...
- Data field, 35... Frame check sequence field, 36... Redundancy field.

Claims (1)

[Claims] A plurality of stations each having a station address are connected to a common transmission path, and the station that intends to transmit has a synchronization code field, a partner station address field that specifies the destination station, and the own station that indicates the source. From the address field, the data length field indicating the length of the data field containing control information, the data field containing control information, and the bit pattern from the first bit of the partner station address field to the last bit of the data field. Desired,
A frame consisting of a frame check sequence field that stores a frame check sequence and a redundant field with a length that requires transmission time more than twice the transmission delay time that occurs in the entire network is transmitted when the transmission path is empty. If it is detected that a collision has occurred on the transmission path due to frame transmission from another station during the transmission of the synchronization code field, the transmission is stopped, and after waiting for a time determined by a random number, the transmission is repeated again. After confirming the availability of the transmission path and transmitting the frame, each station connected to the transmission path receives the station address indicated in the partner station address field of the frame after completing synchronization using the synchronization code field of the frame. , and the own station address, and when a matching frame is received, the frame check sequence obtained from the bit pattern from the first bit of the partner station address field to the last bit of the data field, and the frame check of the frame. Compare with the sequence field and if there is a match,
In a transmission control method for an information processing device that includes a network system that captures the frame as a frame addressed to its own station, the system includes a receiving circuit that extracts a frame addressed to its own station from a transmission path, and a determination as to whether there is a frame check sequence error in the received frame. a collision circuit that intentionally causes a collision for the purpose of notifying the source station of the completion of normal reception while receiving the redundant field of the frame addressed to the local station; and a transmission circuit that transmits the frame to the transmission path. , and a collision determination circuit that determines whether a collision has occurred while transmitting the redundant field of the frame, and if the destination station is able to correctly receive the frame, the transmitter has a collision determination circuit that determines whether a collision has occurred while transmitting the redundant field of the frame. A transmission control method that notifies successful reception by intentionally causing a collision.