JPH05336194A - Data transmission system - Google Patents

Abstract

PURPOSE:To improve a data efficiency by performing consecutive transmission of an information frame while no response is confirmed and immediately replying a returned response confirmation. CONSTITUTION:A transmission means 11 continuously transmits an information frame without taking confirmation of a response from a response means 21, and transmits with a pole bit of the information frame to be transmitted next set to 1 based on the coincidence result between a maximum out standing number from a counter means 12 and the number of the transmitted information frames. The transmission means 11 receives the response frame whose final bit from the response means is 1 and sets the pole bit of the information frame to 0 again and the information frame is transmitted continuously without taking confirmation of response from a data receiver.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a data transmission system according to a high level data link control procedure. In particular, high-level data link control procedures (HDLC, High
LevelData Link Control Pr
The present invention relates to a data transmission method for performing efficient data transmission by controlling a poll bit (hereinafter, referred to as P bit) in a control field of an information frame (hereinafter, referred to as I frame) in an occupure).

[0002]

2. Description of the Related Art FIG. 4 is a sequence diagram of a data frame when an I frame having all P bits set to "0" in the conventional data transmission method is transmitted. FIG. 5 is a sequence diagram of a data frame when all P bits of the conventional data transmission method are set to "1".

Conventionally, as shown in FIG. 4, the data transmission method is based on SABM (set async) from a data transmission device.
A UA (unnu) from a hornous balanced mode command frame and a data receiving device.
After establishment of a link by an mbred acknowledged) response frame, I frames with all P bits set to “0” are continuously transmitted, and an I frame is normally received by an RR (receive ready) response frame from the data receiving device. Is returned as a response confirmation.

Further, in FIG. 5, I frames in which all P bits are set to "1" are continuously transmitted.

In the high-level data link control procedure, the data transmitter can transmit the I frame up to the maximum outstanding number (K) of I frames even if the response is not confirmed, but the next I frame is transmitted until the response is confirmed. It is decided to ban. Further, in the high-level data link control procedure, the data receiving device may return a response frame in which the final bit (F bit) is "0" at an arbitrary time after receiving the command frame in which the P bit is "0". When a command frame of bit "1" is received, it is decided to immediately return a response frame of F bit "1".

[0006]

However, in such a conventional data transmission method, in the case shown in FIG. 4, when an I frame in which all P bits are set to "0" is continuously transmitted, the data transmission device Even when the maximum number of outstanding I-frames (K) has been transmitted and waiting for the confirmation of the response constantly, it may be slow for the data receiving device to return the response confirmation. There has been a problem that the time for which transmission is prohibited becomes long and the data transmission efficiency deteriorates.

Further, in the case shown in FIG. 5, when I frames whose P bits are all set to "1" are continuously transmitted, one response confirmation (RR) frame is always returned for one I frame. Further, there is a problem that the data transmission efficiency is not improved because the continuous transmission of the I frame is prohibited due to the unconfirmed response.

The present invention solves the above problems.
An object of the present invention is to provide a data transmission method capable of continuously transmitting information frames without confirmation of a response, and returning a response confirmation immediately to improve data transmission efficiency.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to a data transmission side device for transmitting data based on a high level data link control procedure, and a data reception side device for receiving data from this data transmission device via a transmission path. The data transmitting side device transmits the information frame after the link is established by continuously transmitting the information frame by setting the poll bit to "0" without confirming the response of the data receiving side device. Counting means for counting the number of information frames and outputting a coincidence signal when the counting result reaches a predetermined maximum outstanding number, when the data receiving side device receives the information frames from the transmitting means. When the poll bit is "1", the data transmission including response means for immediately returning the response frame with the final bit set to "1" is returned. In the method, the transmitting means receives means for transmitting an information frame to be transmitted next based on the result of the coincidence, with its poll bit set to "1", and a response frame having a final bit of "1" from the response means. Means for continuously transmitting the information frame with the poll bit set to "0" without confirming the response of the data receiving side device.

Further, according to the present invention, the frame structure of the above high level data link control procedure includes a first flag sequence, an address part, a control part, an information part, a frame check sequence and a last flag sequence. In addition, the control unit may include a poll bit for a command frame and a final bit for a response frame.

[0011]

The transmitting means transmits the information frame to be transmitted next with the poll bit set to "1" on the basis of the result of coincidence between the predetermined maximum outstanding number from the counting means and the number of transmitted information frames, and responds. A response frame whose final bit is "1" is received from the means, and the information frame is continuously transmitted without checking the response of the data receiving side device by setting the poll bit to "0".

As described above, the information frame can be continuously transmitted without confirming the response, and the response confirmation can be immediately returned to improve the data transmission efficiency.

[0013]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a data transmission system according to an embodiment of the present invention.

In FIG. 1, the data transmission method is a data transmission apparatus 10 capable of data transmission / reception or data transmission as a data transmission side apparatus for transmitting data based on a high-level data link control procedure, and data from the data transmission apparatus 10. And a data receiving device 20 capable of data transmission / reception or data reception as a data receiving side device for receiving via a wired or wireless transmission path 30. The transmission means 11 which continuously sets the data reception device 20 to “0” without confirming the response of the data reception device 20 and the number of I frames transmitted by the transmission means 11 are counted, and the counting result becomes a predetermined maximum outstanding number (K). Counting means 12 which outputs a coincidence signal when The P upon receiving the I frame
When the bit is "1", a response means 21 for returning the response frame with its final bit (hereinafter referred to as F bit) set to "1" is immediately returned.

Here, the feature of the present invention is that the transmission means 11 transmits the I frame to be transmitted next based on the above-mentioned coincidence result by setting the P bit to “1” and the response means 21. It is to include means for receiving a response frame in which the F bit is “1”, setting the P bit in the I frame to “0”, and continuously transmitting without receiving confirmation of the response of the data receiving device 20.

The operation of the data transmission system having such a configuration will be described. FIG. 2 is a sequence diagram of a data frame when the maximum number of outstanding states in the data transmission method of the present invention is three. FIG. 3 is a sequence diagram of a data frame when the maximum number of outstanding states in the data transmission method of the present invention is 7.

In FIGS. 1 and 2, when the data transmitter 10 wants to transmit data to the data receiver 20, the link is established by the SABM or SABME command frame and the UA response frame in the high level data link control procedure. Then, the I frame can be transmitted and received. After the link is established, the counting means 12 in the data transmission device 10 initializes a counter K for the number of I-frame transmissions (outstanding number) for which a response has not been confirmed to "0". Every time an I frame is transmitted, "1" is added to the counter K, and conversely, when a response confirmation is obtained from the data receiving device, the number of counters is reduced by the number of frames for which the response confirmation is made. When the counter value K reaches "2", a coincidence signal is output. When the counter value of the outstanding number is less than the maximum outstanding number 3 of the I frame without the coincidence signal from the counting means 12, the transmitting means 11 sets the P bit in the control unit to “0” and sets it to I. Frame (NS
= 0, 1) is transmitted, but the counter value K of the outstanding number becomes equal to the maximum outstanding number 3 of the I frame after receiving the coincidence signal (NS) (NS
= 2), the P bit in the control unit of the I frame is set to "1" and the I frame is transmitted. Upon reception of the P-bit “1” command frame, the response unit 21 immediately returns a response confirmation for three frames, and the counting unit 12 having received the response confirmation reduces the outstanding number counter value to “0”. The transmitting means 11 becomes ready to transmit the next I frame (NS = 3).

When the maximum number of outstanding I frames (K) is set to "3", specifically, the D channel packet exchange in the INS Net 64 service provided by Nippon Telegraph and Telephone Corporation is performed. The maximum number of outstanding I-frames (K) corresponding to the case of using B channel packet switching in the INS Net 64 service.
The case of "7" is shown in FIG. When the maximum outstanding number (K) of the I frame is set to "7" as well as when it is set to 3, when the count value of the outstanding number becomes equal to "7", the poll bit in the I frame Is set to "1" and transmitted.

[0019]

As described above, the present invention has an excellent effect that the information frame can be continuously transmitted without confirmation of the response, and the response confirmation is immediately returned to improve the data transmission efficiency.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of a data transmission system according to an embodiment of the present invention.

FIG. 2 is a sequence diagram of a data frame when the maximum outstanding number of the data transmission method of the present invention is “3”.

FIG. 3 is a sequence diagram of a data frame when the maximum outstanding number of the data transmission method of the present invention is “7”.

FIG. 4 is a sequence diagram of a data frame when an I frame in which all the poll bits are set to “0” in the conventional data transmission method is transmitted.

FIG. 5 is a sequence diagram of a data frame when an I frame in which all the poll bits are set to “1” in the conventional data transmission method is transmitted.

[Explanation of symbols]

 10 data transmitting device 11 transmitting means 12 counting means 20 data receiving device 21 responding means

Claims (2)

[Claims] 1. A data transmission side device for transmitting data based on a high-level data link control procedure, and a data reception side device for receiving data from the data transmission device via a transmission path. After the link is established, the device counts the number of information frames transmitted by the transmitting means and the transmitting means for continuously transmitting the information frame by setting the poll bit to "0" without confirming the response of the data receiving side device and counting the number. Counting means for outputting a coincidence signal when the result reaches a predetermined maximum outstanding number, and the data receiving side apparatus has a poll bit of "1" when receiving the information frame from the transmitting means. Occasionally, in a data transmission system including a response means for immediately returning a response frame with its final bit set to "1", The means sets the poll bit of the information frame to be transmitted next based on the match result to "1", and the final bit from the response means is "1".
And a means for continuously transmitting the information frame by setting the poll bit of the information frame to "0" and not confirming the response of the data receiving side device. 2. The frame structure of the high-level data link control procedure includes a first flag sequence, an address part, a control part, an information part, a frame check sequence, and a last flag sequence. Department is
The data transmission system according to claim 1, wherein a poll bit is included in a command frame, and a final bit is included in a response frame.