JP2980646B2 - Frame retransmission method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a frame retransmission method in a data communication device for transferring a frame via a multilink composed of a plurality of single links. Aiming to complete the transfer to the opposing device quickly and reliably, each single link mechanism detects that the same frame has been retransmitted a predetermined number of times on the corresponding single link, and notifies the multilink mechanism of retransmission. When a retransmission notification is received from an arbitrary single link mechanism forming a single link constituting a multilink, the multilink mechanism requests a transfer to the single link mechanism and the transfer is not completed. Other single link machines that form a single link that constitutes a multilink with all frames of A configuration is provided in which a plurality of frame request changing means for requesting a frame is provided.

[Industrial applications]

The present invention relates to a frame retransmission method in a data communication device that transfers a frame via a multilink composed of a plurality of single links.

Data communication devices are connected by a plurality of communication lines, and high-speed, high-speed communication is performed using data links (hereinafter referred to as single links) of transmission control procedures conforming to CCITT recommendation X25 or X75 formed on each communication line. Attempts have been made to construct data links of transmission capacity (hereinafter multilinks).

[Conventional technology]

FIG. 4 is a diagram showing an example of a conventional data communication device, and FIG. 5 is a diagram showing an example of a frame retransmission method in FIG.

In FIG. 4, the data communication device is composed of two sets of communication lines 5 (each communication line is 5-1 and 5-) connected to the same data communication device (hereinafter, referred to as an opposite device) not shown.
2 and the same shall apply hereinafter).
, A line interface unit (PLC) 4 and a single link mechanism (SLP) 3 are provided respectively.

Each single link mechanism (SLP) 3 forms a single link SL of a transmission control procedure based on, for example, CCITT Recommendation X25 on the corresponding communication line 5.

Further, the data communication device is provided with each single link mechanism (SL
P) 3 is provided with a multilink mechanism (MLP) 2 in common, and each single link mechanism (SLP) 3-1 and 3-2
Form a multilink ML on single links SL-1 and SL-2 formed on the corresponding communication lines 5-1 and 5-2, respectively.

4 and 5, a packet conversion processing unit (PSC) 1 transmits three sets of data packets DT (DT) to be transferred to an opposing device via a multilink ML constituted by a multilink mechanism (MLP) 2. 0.0), DT (1.0) and DT (2.
0) to the multi-link mechanism (MLP) 2, the multi-link mechanism (MLP) 2 transmits each transmitted data packet D
Multilink frames M (0), M (1) and M (0) are added to T (0.0), DT (1.0) and DT (2.0) by adding a multilink control field including a multilink transmission sequence number.
(2) Edit (however, (0), (1) and (2) indicate the multilink transmission sequence number), and sequentially transmit to one single link mechanism (SLP) 3-1 to request transfer and , Transmitted multilink frames M (0), M
(1) and M (2) are converted to a single link mechanism (SLP)
3-1 is stored in the frame register (FRG) 21-1.

The single link mechanism (SLP) 3-1 is a multilink frame M transmitted from the multilink mechanism (MLP) 2.
(0), M (1) and M (2) are linked to the transmission queue (QUE) 31-1 in the order of arrival, and then the transmission queue (QUE) 31-1
, A leading multilink frame M (0) is extracted, an information frame I (0.0) based on a predetermined transmission control procedure is edited, and the information frame I (0.0) is placed on the communication line 5-1 via the line interface unit (PLC) 4-1. It is transmitted to the formed single link SL-1.

The transmitted information frame I (0.0) is transmitted to the communication line 5-
1 to the opposing device, the opposing device checks the reception of the information frame I (0.0) by the check frame RR (.
1) is returned to the single link mechanism (SLP) 3-1 via the single link SL-1.

The single link mechanism (SLP) 3-1 receiving the check frame RR (.1) notifies the multilink mechanism (MLP) 2 that the transfer of the multilink frame M (0) has been completed. RR (.1) with multi-link mechanism (ML
P) 2 and the transmission queue (QUE) 31−
Then, the next multilink frame M (1) is extracted from 1, and the information frame I (1.0) is edited and transmitted to the single link SL-1 in the same manner as described above.

The multilink mechanism (MLP) 2 that has received the check frame RR (.1) recognizes that the transfer of the multilink frame M (0) has been completed, and receives the frame register (FRG) 21-.
1 deletes the multilink frame M (0) stored in 1.

At this time, when a failure occurs in the communication line 5-1 and the monitoring frame RR (.2) for confirming the reception of the information frame I (1.0) is not returned from the opposite device, the single link mechanism (SLP) 3- 1 measures the elapsed time since the transmission of the information frame I (1.0), and if the monitoring frame RR (.2) is not returned even after the predetermined time T has elapsed, the information frame I (1.0) is again transmitted. To the single link SL-1.

If the failure of the communication line 5-1 is not repaired, and the monitoring frame RR (.2) is not returned even after a predetermined time T has elapsed after retransmission, the single link mechanism (SLP) 3-1 sends the information frame I Repeat (1.0) retransmission.

On the other hand, the MN1 retransmission processing unit (MN1C) 32-1 in the single link mechanism (SLP) 3-1 is a single link mechanism (SLP)
The number of retransmissions of the information frame I (1.0) according to 3-1 is counted. When the number of retransmissions reaches a predetermined number (for example, one MN according to the recommendation X25), the multilink mechanism (MLP) 2 On the other hand, the multilink frame M (1)
MN1 retransmission notification MN1 to notify N1 retransmission
[M (1)] is transmitted to the multilink mechanism (MLP) 2, and the retransmission of the information frame I (1.0) is continued.

The multilink mechanism (MLP) 2 that has received the MN1 retransmission notification MN1 [M (1)] activates the single frame retransmission unit (SFC) 22.

When the activated single frame retransmission unit (SFC) 22 recognizes that the multilink frame M (1) is not transferred to the intermediate device via the single link SL-1, the single frame retransmission unit (SFC) 22 transmits the multilink frame M (1) from the frame register (FRG) 21-1. Multilink frame M
Extract (1) and the other single link mechanism (SLP) 3
And a request for transfer to the opposing device is stored in the frame register (FRG) 21-2 corresponding to the single link mechanism (SLP) 3-2.

The single link mechanism (SLP) 3-2 connects the multilink frame M (1) transmitted from the multilink mechanism (MLP) 2 to the transmission queue (QUE) 31-2 and transmits The multilink frame M (1) is extracted from the queue (QUE) 31-2, the information frame I (0.0) based on a predetermined transmission control procedure is edited, and communication is performed via the line interface unit (PLC) 4-2. The signal is transmitted to the single link SL-1 formed on the line 5-2.

On the other hand, in the single link mechanism (SLP) 3-1 that continues to retransmit the information frame I (1.0), the N2 times retransmission processing unit (N2C) 33-1 has the single link mechanism (SLP) 3.
−1, the number of retransmissions of the information frame I (1.0) is counted, and the number of retransmissions is a predetermined number larger than a predetermined number of MN1 [for example, N2 times according to the recommendation X25 (where N2 ≧ M
N1)], the single link SL-1 formed on the communication line 5-1 is released once, and then formed again, and the single link SL-L is transmitted to the multi-link mechanism (MLP) 2.
1 is signaled.

Due to the re-creation of the single link SL-1, all the multilink frames M (1) and M (2) connected to the transmission queue (QUE) 31-1 are deleted.

The multi-link mechanism (ML) notified from the single-link mechanism (SLP) 3-1 of the re-creation of the single link SL-1
P) 2 extracts all the multilink frames M (2) stored in the frame register (FRG) 21-1, requests the other single link mechanism (SLP) 3-2 to transfer,
It is stored in the frame register (FRG) 21-2.

[Problems to be solved by the invention]

As is apparent from the above description, in the conventional data communication apparatus, the single link mechanism (SLP) 3-1 to M
The multilink mechanism (MLP) 2 that has received the N1 times retransmission notification MN1 [M (1)]
Requesting transfer of only (1) to another single link mechanism (SLP) 3-2, and leaving the remaining multilink frame M (2)
Means that the single link mechanism (SLP) 3-1 is N2 times (N2
≧ MN1), after retrying the transfer to another single link mechanism (SLP) 3-2 at last, it takes a long time until the multilink frame M (2) is reliably transferred. There was a problem to take.

After trying to retransmit information frame I (1.0) MN once,
It is considered that the failure of the communication line 5-1 is recovered until the number of retransmissions reaches N2, and the transfer of the information frame I (1.0) is completed. (1.0) is extremely unlikely to complete the transfer before retransmitting N2 times.

SUMMARY OF THE INVENTION It is an object of the present invention to complete the transfer of information transferred via a multilink to an opposing device as quickly and reliably as possible.

[Means for solving the problem]

 FIG. 1 is a diagram showing the principle of the present invention.

In FIG. 1, 2 is a multilink mechanism, 3 is a single link mechanism, and 5 is a communication line.

Reference numeral 100 denotes retransmission notification means provided in each single link mechanism 3 according to the present invention.

Reference numeral 200 denotes a plural frame request changing unit provided in the multilink mechanism 2 according to the present invention.

[Action]

The single link mechanism 3 forms a single link on each corresponding single communication line 5.

The multilink mechanism 2 forms a multilink on a plurality of single links, and requests the plurality of single link mechanisms 3 corresponding to each single link to transfer a frame.

The retransmission notifying unit 100 detects that the same frame has been retransmitted for the corresponding single link a predetermined number of times, and notifies the multilink mechanism 2 of the retransmission.

When receiving a retransmission notification from an arbitrary single link mechanism 3 forming a single link constituting a multilink, the plural frame request changing means 200 requests all the single link mechanisms 3 to transfer the data and has not completed the transfer. Request is changed to another single link mechanism 3 that forms a single link that forms a multilink.

Note that the retransmission notifying means 100 transmits the same frame to the CCITT recommendation X2.
When retransmission is attempted once in MN indicated by 5 or X75, notification of retransmission is considered.

Therefore, all untransferred frames requested to the single link mechanism that has sent the retransmission notification are quickly and reliably transferred to the opposing device, and the reliability and transmission capability of the data communication device are improved.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Second
FIG. 3 is a diagram showing a data communication device according to an embodiment of the present invention, and FIG. 3 is a diagram showing an example of a frame retransmission method in FIG. The same reference numerals indicate the same objects throughout the drawings.

Also in FIG. 2, the data communication apparatus accommodates two communication lines 5 as in FIG. 4, and two single link mechanisms (SLPs) 3 and 2 corresponding to each communication line 5 respectively. A line interface unit (PLC) 4 is provided, and a packet switching processing unit (PSC) 1 and a multilink mechanism (MLP) 2 are provided in common.

Each single link mechanism (SLP) 3 is, as described above,
A single link SL is formed on the corresponding communication line 5, and a multilink mechanism (MLP) 2 forms a multilink ML on the single links SL-1 and SL-2 in the same manner as described above.

Each single link mechanism (SLP) 3 is provided with an MN once retransmission processing unit (MN1C) 32 as a retransmission notification unit 100 in FIG.
P) 2 includes a plural frame request changing means 2 in FIG.
As 00, a multiple frame retransmission unit (MFC) 23 is provided.

2 and 3, a packet switching processing unit (PSC) 1 transmits three sets of data packets DT (0.0) to be transferred to an opposite device via a multilink constituted by a multilink mechanism (MLP) 2. ), DT (1.0) and DT (2.
0) to the multi-link mechanism (MLP) 2, the multi-link mechanism (MLP) 2 transmits each transmitted data packet D
Multilink frames M (0), M (1) and M (1) are added to T (0.0), DT (1.0) and DT (2.0) by adding a multilink control field including a multilink transmission sequence number.
Edit (2), one single link mechanism (SLP) 3
-1 in sequence, requesting transfer, and transmitting the transmitted multilink frames M (0), M (1) and M
(2) is stored in the frame register (FRG) 21-1 corresponding to the single link mechanism (SLP) 3-1.

The single link mechanism (SLP) 3-1 is a multilink frame M transmitted from the multilink mechanism (MLP) 2.
(0), M (1) and M (2) are linked to the transmission queue (QUE) 31-1 in the order of arrival, and then the transmission queue (QUE) 31-1
, A leading multilink frame M (0) is extracted, an information frame I (0.0) based on a predetermined transmission control procedure is edited, and the information frame I (0.0) is placed on the communication line 5-1 via the line interface (PLC) 4-1. It is transmitted to the formed single link SL-1.

The transmitted information frame I (0.0) is transmitted to the communication line 5-
1 to the opposing device, the opposing device checks the reception of the information frame I (0.0) by the check frame RR (.
1) is returned to the single link mechanism (SLP) 3-1 via the single link SL-1.

The single link mechanism (SLP) 3-1 receiving the check frame RR (.1) notifies the multilink mechanism (MLP) 2 that the transfer of the multilink frame M (0) has been completed. RR (1) is connected to the multilink mechanism (ML
P) 2 and the transmission queue (QUE) 31−
Then, the next multilink frame M (1) is extracted from 1, and the information frame I (1.0) is edited and transmitted to the single link SL-1 in the same manner as described above.

The multilink mechanism (MLP) 2 that has received the check frame RR (.1) recognizes that the transfer of the multilink frame M (0) has been completed, and receives the frame register (FRG) 21-.
1 deletes the multilink frame M (0) stored in 1.

At this time, when a failure occurs in the communication line 5-1 and the monitoring frame RR (.2) for confirming the reception of the information frame I (1.0) is not returned from the opposite device, the single link mechanism (SLP) 3- 1 measures the elapsed time from the transmission of the information frame I (1.0). If the monitoring frame RR (.2) is not returned even after the predetermined time T has elapsed, the information frame I (1.0) is re-transmitted. Send to single link SL-1.

If the failure of the communication line 5-1 is not repaired, and the monitoring frame RR (.2) is not returned even after a predetermined time T has elapsed after retransmission, the single link mechanism (SLP) 3-1 sends the information frame I Repeat (1.0) retransmission.

On the other hand, the MN1 retransmission processing unit (MN1C) 32-1 in the single link mechanism (SLP) 3-1 is a single link mechanism (SLP)
The number of retransmissions of the information frame I (1.0) according to 3-1 is counted, and the number of retransmissions is a predetermined number (for example, MN1).
Times), the MN1 retransmission notification MN1 [M (1)] is sent to the multilink mechanism (MLP) 2 to notify the multilink mechanism (MLP) 2 that the multilink frame M (1) has been retransmitted MN1 times. (MLP) 2 and continue retransmission of the information frame I (1.0).

The multilink mechanism (MLP) 2 that has received the MN1 retransmission notification MN1 [M (1)] activates the multi-frame retransmission unit (MFC) 23.

When the activated multi-frame retransmission unit (MFC) 23 recognizes that the multilink frame M (1) and the subsequent frames are not transferred to the intermediary device via the single link SL-1, the multi-frame retransmission unit (MFC) 23 stores it in the frame register (FRG) 21-1. It extracts all the multilink frames M (1) and (2) that have been stored and requested to be transferred to the single link mechanism (SLP) 3-1 and have not been transferred, and extract the other single link mechanism (SLP). 3
And a request for transfer to the opposing device is stored in the frame register (FRG) 21-2 corresponding to the single link mechanism (SLP) 3-2.

The single link mechanism (SLP) 3-2 places the multilink frames M (1) and M (2) transmitted from the multilink mechanism (MLP) 2 in the transmission queue (QUE) 31-2 in the same manner as described above. After connection, transmission queue (QUE) 31-2
, The multilink frames M (1) and M (2) are sequentially extracted from the information frame I based on a predetermined transmission control procedure.
(0.0) and I (1.0) are edited and transmitted to the single link SL-2 formed on the communication line 5-2 via the line interface unit (PLC) 4-2.

As is apparent from the above description, according to the present embodiment, the single link mechanism (SLP) 3-1 sends the MN1 retransmission notification MN1 once.
Multilink mechanism (MLP) 2 receiving [M (0)]
Considers that there is a high possibility that the single link set by the single link mechanism (SLP) 3-1 will be formed again,
Request to transfer all multilink frames M (1) and M (2) that have been requested to be transferred to the single link mechanism (SLP) 3-1 and have not been transferred to another single link mechanism (SLP) 3-2. All the multi-link frames M
(1) and M (2) are promptly transferred to the opposing device.

FIG. 2 and FIG. 3 are merely examples of the present invention.
Is not limited to two lines, and many other modifications are considered, but the effect of the present invention does not change in any case. The configuration of the data communication device that is the object of the present invention is as follows.
It goes without saying that the present invention is not limited to the illustrated one.

〔The invention's effect〕

As described above, according to the present invention, in the data communication device, all uncompleted transfer frames requested to the single link mechanism that has sent the retransmission notification are quickly and reliably transferred to the other device. The reliability and transmission capacity of the device are improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing the principle of the present invention, FIG. 2 is a diagram showing a data communication apparatus according to an embodiment of the present invention, FIG. 3 is a diagram showing an example of a frame retransmission system in FIG. 2, and FIG. FIG. 5 is a diagram showing an example of a conventional data communication device, and FIG. 5 is a diagram showing an example of a frame retransmission method in FIG. In the figure, 1 is a packet switching processing unit (PSC), 2 is a multilink mechanism (MLP), 3 is a single link mechanism (SL
P), 4 is a line interface section (PLC), 5 is a communication line, 21 is a frame register (FRG), 22 is a single frame retransmitting section (SFC), 23 is a multiple frame retransmitting section (MFC), and 31 is a transmission waiting section. Matrix (QUE), 32 is MN1 retransmission processing unit (MN1C), 33
Denotes an N2 retransmission processing unit (N2C), 100 denotes a retransmission notification unit, and 200 denotes a multiple frame request change unit.

Claims (2)

(57) [Claims] 1. A plurality of single link mechanisms for forming a single link on a corresponding single communication line, and a multilink formed on the plurality of single links, requesting each of the single link mechanisms to transfer a frame. In the data communication device having a multi-link mechanism, the single link mechanism detects that the same frame has been retransmitted a predetermined number of times on the corresponding single link, and notifies the multi-link mechanism of retransmission. Providing retransmission notification means for performing, when the multilink mechanism receives the retransmission notification from any single link mechanism that forms the single link, immediately requests the single link mechanism to transfer and the transfer is not completed A multi-frame request changing means for requesting all frames to another single link mechanism is provided. That, a frame retransmission scheme, wherein. 2. The retransmission notifying means according to claim 1,
The frame retransmission method according to claim 1, wherein the retransmission notification is performed when retransmission is attempted once in MN indicated in T recommendation X25 or X75.