JPH05122287A - Hdlc procedure data transfer equipment - Google Patents

Abstract

PURPOSE:To distinguish whether a cause to a fault in frame transmission is due to transmission clock interruption or an error on a transmission line or the fault of an opposite station without the provision of any complicated electronic circuit to detect the interruption of a transmission clock by utilizing a T1 timer for the control of the HDLC procedure. CONSTITUTION:When a sender side equipment 1 starts frame transmission, a transmission clock interruption detection flag is set to start a T1 timer 10. Upon the receipt of a reply frame from a receiver side equipment 2 with respect to frame transmission, the T1 timer 10 is stopped. When the occurrence of T1 expiration is detected, set/reset state of a transmission clock detection flag is discriminated and when the frame transmission is finished before the expiration of the T1 timer, the transmission line error processing or opposite station fault processing is implemented, When T1 expiration takes place before the end of frame transmission, the transmission clock interrupt detection processing is implemented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an HDLC procedure data transfer apparatus, and more particularly to discrimination of causes of occurrence of abnormal frame transmission.

[0002]

2. Description of the Related Art A conventional device is used to detect an abnormality in frame transmission.
Whether or not it is due to the transmission clock loss, due to an error on the transmission path, or due to an abnormality in the partner station, or when they are distinguished, a complicated electronic circuit is used to detect the transmission clock loss.

[0003]

The conventional device detects a transmission clock loss in order to distinguish an abnormality in frame transmission from a transmission clock loss, an error on the transmission path, or an abnormality in the partner station. There was a problem that a complicated electronic circuit for

An object of the present invention is to provide an HDLC procedure for distinguishing a frame transmission abnormality from a transmission clock loss, a transmission path error or a partner station abnormality without requiring a complicated electronic circuit for detecting a transmission clock failure. It is to provide a data transfer device.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a T1 timer is provided in a transmission side apparatus in order to discriminate an abnormality in frame transmission from a transmission clock loss, an error on a transmission path, or an abnormality in a partner station. Characteristic, HDLC
It is a procedure data transfer device.

According to the present invention, in the HDLC procedure, frame transmission is performed in synchronization with the transmission clock. Therefore, when there is no transmission clock interruption, a response frame is received from the partner station before T1 timeout occurs, When the transmission clock is cut off, T1 timeout occurs before the frame transmission is completed. Thus, when T1 timeout occurs,
It is possible to detect whether or not the transmission clock is broken by judging whether or not the frame transmission is completed.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of the configuration of the present invention, and FIG. 2 is a flow chart showing an embodiment of the present invention. As shown in FIG. 1, the transmission side device 1 having the T1 timer 10 transmits a frame in the HDLC procedure, and the reception side device 2 receives the response frame. FIG. 2 shows the transmitting side device 1.
2 is an example of a flowchart in FIG.

(102), (103), (104),
(105) and (106) set the transmission clock loss detection flag at the start of frame transmission and start the T1 timer. (107) and (108) reset the transmission clock loss detection flag when the frame transmission is completed.
(109) and (110) stop the T1 timer when a response frame is received from the partner station in response to the frame transmission. When the occurrence of T1 timeout is detected in (111), the transmission clock loss detection flag is set in (112).
If the reset state is judged and the frame transmission is completed before the T1 timeout, an error on the transmission path occurs in (115),
Alternatively, if the T1 timeout occurs before the frame transmission is completed, the partner station abnormality processing is performed (113), the transmission clock loss detection processing.

[0009]

As described above, according to the present invention, the HDL
By using the T1 timer, which is indispensable for controlling the C procedure, even if there is no complicated electronic circuit for detecting the transmission clock loss, the cause of the frame transmission abnormality is due to the transmission clock loss, a transmission line error, or This has the effect of distinguishing whether or not it is due to an abnormality in the partner station.

[Brief description of drawings]

FIG. 1 is a block diagram of a configuration of the present invention,

FIG. 2 is a flowchart of an embodiment of the present invention.

[Explanation of symbols]

 1 transmitting side device 2 receiving side device 10 T1 timer

Claims (1)

[Claims] 1. An HDLC procedure data, characterized in that a T1 timer is provided in a transmitting side device for distinguishing an abnormality in frame transmission from a transmission clock interruption, an error on a transmission path or an abnormality in a partner station. Transfer device.