JPH0492541A - Delay system for information receiving time of communication protocol - Google Patents

Abstract

PURPOSE:To secure a normal sequence even if much time is needed for collection of the information on a secondary station by providing a timer to a primary station to wait for reception of an information frame from a secondary station and waiting for reception of the information. CONSTITUTION:A one-frame reception waiting timer is used as a WAIT timer to a normal time-out monitor timer, and the waiting time counted by the WAIT timer is never set in a time-out state. At a primary station, the WAIT timer is started after transmission a single frame and the RR information is received after a fixed time. Meanwhile at a secondary station, the RR information is returned if the collection of information is impossible even in a normal operation state. Thus another timer is started for waiting the reception of information when much time is needed for collection of the information given from an additional device at the secondary station of the remote side and furthermore a time-out state is erroneously set at its own station side. Then the waiting time can be freely set as a normal sequence for reception of information.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an information reception time delay method of a communication protocol, and particularly to an HDLC (high level data link control method).
The present invention relates to an information reception time delay method for a communication protocol that delays the time for waiting for information reception when it takes time to return information from a device on the other side using a compliant communication protocol.

[Prior Art] When communication is performed between a primary station and a secondary station using an HDLC-compliant communication protocol, various commands and response information are used. An example of such communication is shown in FIG.

In FIG. 2, a primary station communicates with a secondary station. In addition, the second
In the figure, one arrow corresponds to one frame. first,
The primary station uses S N RM (Set NormalRe
(sponse Mode) information 21 is sent to the secondary station. 2
When the next station receives this SNRM information 21, the UA (
(Unnumbered Acknowledgment) information 22 is sent to the primary station. Information is thereby transmitted.

The information is transmitted in the l ()nformation: information) frame 23, and the secondary station that receives this from the primary station sends the ■ frame 24 as a response to the information from the primary station.
Send.

After that, the primary station receives RR (Receive Ready:
When the information 25 (receivable) is sent to the secondary station, the secondary station receives the RR information,
26 is sent to the primary station. Then, the primary station is DISC (
Disconnect) information 27 is sent to the secondary station, and when the secondary station sends UA information 28, the communication ends.

By the way, the primary station that performs such communication has a timer for waiting for a reply from the secondary station. Usually the timer is 0
It times out in seconds (n is arbitrary, but not very large), and at this time the same frame is retransmitted or an RR is sent. Furthermore, if a timeout occurs consecutively (k is arbitrary, usually about 3 times), the primary station will be forced to
Aborts communication with the next station.

[Problem to be solved by the invention]

When communication is performed using such an HDLC-compliant communication protocol, it sometimes takes time for the secondary side to reply. For example, this is the case when a secondary station collects information from another device to send back to the primary station.

This situation is shown in FIG. That is, when the secondary station sends the UA information 32 in response to the SNRM information 31, the primary station sends the ■ frame 33 and starts the timer. 2
The next station receives frame 33 and starts collecting information. If the secondary station cannot complete collecting information and times out, the primary station sends RR information 34 to the secondary station. after that,
Timeout occurs again, and the primary station sends RR information 3 to the secondary station.
5 is sent and communication is terminated.

As described above, even if the secondary station is operating normally, if it takes time to collect and send back information, a timeout will occur on the primary station side and communication will be terminated.

The purpose of the present invention is to eliminate such drawbacks and to
To provide an information reception time delay method for a communication protocol that can delay information reception waiting time even when it takes time for a device at the other end to return information in a communication protocol based on JA.

[Means to solve the problem]

The present invention uses a high-level data link control method to
In the information reception time delay method of the communication protocol in which the next station sends and receives information frames to and from the secondary station, the reception wait timer for waiting for information frame reception from the secondary station is set to 1.
After transmitting the information frame to the secondary station, it starts the reception waiting timer of the primary station, and when the information frame is not returned from the secondary station by the time set in the reception waiting timer, the primary station The station transmits specified information to the secondary station, and when the specified information is received, the secondary station returns an information frame or the specified information to the primary station, and when the information frame is received, the primary station establishes a high-level data link. Communication is performed according to the normal sequence based on the control method, and when a predetermined frame is received, the primary station starts a reception wait timer.

In the present invention described above, it is preferable to use receivable information of the high-level data link control method as the predetermined information transmitted and received between the primary station and the secondary station.

[Example] Next, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sequence diagram showing one embodiment of the present invention, and shows how a primary station communicates with a secondary station. Normally, the timer of the primary station is used for monitoring operations other than (1) frame transmission/reception, so the waiting time cannot be made too long. Therefore, we will use a different timer. In other words, for a normal timeout monitoring timer, I
The timer waiting for frame reception is assumed to be a WAIT timer. The waiting time by this WAIT timer is not considered a timeout. The primary station starts this timer after transmitting the (1) frame, and transmits the RR information after a certain period of time has elapsed. On the other hand, if the secondary station is not able to collect information even though it is operating normally, it will reply with RR information. By repeating this procedure, when the secondary station is able to collect information, the
An I frame is transmitted as a reply to the R information.

Next, the operation of this embodiment will be explained.

First, the primary station sends SNRM information 1 to the secondary station. When the secondary station receives this SNRM information 1, it sends UA information 2 to the primary station. As a result, the primary station sends frame 3 to 2
Send to next station. The primary station ■ WAIT after transmitting frame 3
Start the timer. After receiving the frame (1), the secondary station starts collecting information in response to the received frame.

At this time, the secondary station cannot send a reply to the primary station because it takes time to collect information. The primary station transmits RR information 4 after a certain period of time has elapsed using the WAIT timer. At this time, 2
Since the next station cannot reply yet, it replies with RR information 5. The primary station that has received this RR information 5 starts the WAIT timer again and decides to wait for the secondary station.

After a certain period of time has elapsed, the primary station transmits the second RR information 6.
Send to next station. When the primary station transmits the RR information 6 for the second time, the secondary station has completed collecting information, so it returns frame 7.8. The sequence after this follows the normal sequence.

That is, when the primary station sends RR information 9 to the secondary station, the secondary station sends RR information 10 to the primary station. Then, the primary station sends Disc information II to the secondary station, and the secondary station sends UA information 1.
Sending 2 terminates the communication.

In this way, in the HDLC-compliant communication protocol, if the secondary station on the other side takes time to collect information from the additional device and the local station times out,
A separate timer for waiting for information reception can be started, and the waiting time for information reception can be freely set as a normal sequence.

〔Effect of the invention〕

As explained above, since the present invention uses a reception waiting timer to wait for information reception, the reception waiting time and the number of repetitions can be freely set, and if it takes time to collect information from the secondary station. However, it has the effect that it can be treated as a normal sequence.

[Brief explanation of drawings]

FIG. 1 is a sequence diagram illustrating an embodiment of the present invention, and FIGS. 2 and 3 are sequence diagrams when communicating using an HDLC-compliant communication protocol. 1... SNRM information 2.12... UA information 3.7.8... I frame 4.5, 6, 9.10... RR information 11... Disc information

Claims (2)

[Claims] (1) Using the high-level data link control method, in the information reception time delay method of the communication protocol in which the primary station sends and receives information frames to and from the secondary station, the reception wait timer for waiting for information frame reception from the secondary station is set to 1. After transmitting the information frame to the secondary station, it starts the reception waiting timer of the primary station, and when the information frame is not returned from the secondary station by the time set in the reception waiting timer, the primary station The station transmits specified information to the secondary station, and when the specified information is received, the secondary station returns an information frame or the specified information to the primary station, and when the information frame is received, the primary station establishes a high-level data link. An information reception time delay method of a communication protocol, characterized in that communication is performed according to a normal sequence according to the control 1 method, and when a predetermined frame is received, a reception wait timer is started at the primary station. (2) The information reception time delay method of the communication protocol according to claim 1, wherein receivable information of the high-level data link control method is used as the predetermined information transmitted and received between the primary station and the secondary station.