JPH0710074B2 - Communication protocol information reception time delay method - Google Patents

Description

The present invention relates to a method for delaying information reception time of a communication protocol, and in particular, a communication protocol conforming to HDLC (High Level Data Link Control Method) and information from a partner device. The present invention relates to an information reception time delay method of a communication protocol for delaying the information reception waiting time when it takes time to reply.

[Conventional technology]

When communication is performed between the primary station and the secondary station in the HDLC-compliant communication protocol, various command and response information is used. An example of such communication is shown in FIG.

In FIG. 2, the primary station communicates with the secondary station. The second
In the figure, one arrow corresponds to one frame. First,
The primary station sends SNRM (Set Normal Response Mode) information 21 to the secondary station. Upon receiving this SNRM information 21, the secondary station sends UA (Unnumbered Acknowledge) information 22 to the primary station. As a result, information is transmitted. Information is I (Inform
(ation: information) frame 23 is transmitted by the primary station, and the secondary station receives the I frame 24 as a response to the information from the primary station.

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

By the way, the primary station side performing such communication has a timer for waiting for a reply from the secondary station. Normally, the timer is n
Times out in seconds (n is arbitrary, but not so large), and at this time, the same frame is retransmitted or an RR is transmitted. Furthermore, if a timeout occurs k times consecutively (k is arbitrary, usually about 3 times), the primary station forcibly terminates communication with the secondary station.

[Problems to be Solved by the Invention]

When communication is performed using such an HDLC-compliant communication protocol, it may take some time for the secondary side to reply. This is the case, for example, when the secondary station collects information from another device for reply to the primary station.

This is shown in FIG. That is, the secondary station
When the UA information 32 is sent to the SNRM information 31, the primary station sends an I frame 33 and starts a timer. The secondary station receives the I frame 33 and starts collecting information. When the secondary station cannot complete the information collection and times out, the primary station sends the RR information 34 to the secondary station. After that, the time-out occurs again, the primary station sends the RR information 35 to the secondary station, and the communication is terminated.

As described above, even if the secondary station is operating normally, if it takes time to collect and return information, the primary station may time out and communication may be terminated.

An object of the present invention is to eliminate such drawbacks, and in an HDLC-compliant communication protocol, the information reception time of the communication protocol that can delay the information reception waiting time even when it takes time to return information from the partner device. To provide a delay method.

[Means for Solving the Problems]

The present invention uses the high level data link control method to
In the information reception time delay method of the communication protocol in which the next station transmits / receives information frames to / from the secondary station, the reception waiting timer for waiting the reception of the information frame from the secondary station is set to 1
It is provided in the next station, and after the information frame is transmitted from the primary station to the secondary station, the reception waiting timer of the primary station is started. At the primary station, the secondary station waits until the time set in the reception waiting timer. When the information frame is not returned, the predetermined information is transmitted to the secondary station, and when the secondary station receives the predetermined information from the primary station, it returns the information frame or the predetermined information to the primary station. When receiving the information frame from the secondary station,
Communication is performed according to a normal sequence according to the high-level data link control method, and the primary station activates a reception waiting timer when it receives predetermined information from the secondary station.

In the above-mentioned present invention, it is preferable to use the 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, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sequence diagram showing an embodiment of the present invention, showing how a primary station communicates with a secondary station. Normally, the timer of the primary station is used for monitoring other than the transmission / reception of I-frames, and therefore the waiting time cannot be made too long. Therefore, a timer other than this is used. That is, for a normal timeout monitoring timer,
The timer waiting for I frame reception is the WAIT timer. this
The waiting time by the WAIT timer does not time out.
The primary station starts this timer after transmitting the I frame, and transmits the RR information after a certain period of time has elapsed. On the other hand, if the secondary station does not collect information despite normal operation, it will return RR information. By repeating this procedure, the secondary station transmits an I frame as a reply to the RR information when the information is collected.

Next, the operation of this embodiment will be described.

First, the primary station sends the SNRM information 1 to the secondary station. Upon receiving this SNRM information 1, the secondary station sends UA information 2 to the primary station. This causes the primary station to send I-frame 3 to the secondary station. The primary station starts the WAIT timer after transmitting the I frame 3. After receiving the I frame, the secondary station starts collecting information as a reply to the I frame.

At this time, the secondary station takes time to collect the information and cannot reply to the primary station. The primary station returns the RR information 4 after the elapse of a certain time by the WAIT timer. At this time, the secondary station cannot reply, so it returns RR information 5. this
The primary station receiving the RR information 5 starts the WAIT timer again and waits for the secondary station.

After the elapse of a certain time, the primary station sends the second RR information 6 to the secondary station. When the primary station transmits the second RR information 6,
Since the secondary station has completed the information collection, the I-frame
Reply 7,8. The subsequent sequence follows the normal sequence. That is, when the primary station sends the RR information 9 to the secondary station, the secondary station sends the RR information 10 to the primary station. Then 1
The communication ends when the next station sends the DISC information 11 to the secondary station and the secondary station sends the UA information 12.

As described above, in the present embodiment, in the HDLC-compliant communication protocol, when the partner secondary station takes time to collect information from the additional device and the local station times out, another timer for waiting for information reception is provided. Can be started and the waiting time for receiving information can be freely set as a normal sequence.

〔The invention's effect〕

As described above, according to the present invention, since the reception waiting timer is used to wait for information reception, it is possible to freely set the reception waiting time, the number of times of repetition, etc., and when it takes time for the secondary station to collect information. However, it has an effect that it can be handled as a normal sequence.

[Brief description of drawings]

FIG. 1 is a sequence diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are sequence diagrams when communication is performed by 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. A high level data link control system,
In the information reception time delay method of the communication protocol in which the primary station transmits / receives the information frame to / from the secondary station, the reception waiting timer for waiting the information frame reception from the secondary station is set to 1
It is provided in the next station, and after the information frame is transmitted from the primary station to the secondary station, the reception waiting timer of the primary station is started. At the primary station, the secondary station waits until the time set in the reception waiting timer. When the information frame is not returned, the predetermined information is transmitted to the secondary station, and when the secondary station receives the predetermined information from the primary station, it returns the information frame or the predetermined information to the primary station. When receiving the information frame from the secondary station,
A method of delaying information reception time of a communication protocol, characterized in that communication is performed according to a normal sequence by a high-level data link control method, and the primary station activates a reception waiting timer when predetermined information is received from the secondary station. . 2. The information reception time delay method according to claim 1, wherein the 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.