JPS62299142A - Packet retransmission control system - Google Patents

Abstract

PURPOSE:To remarkably reduce the holding time of a retransmission buffer by allowing a reception exchange station to send a transmission acknowledgement between stations to be returned to a sending exchange station automonously without awaiting the incoming of the transmission acknowledgement from a reception terminal equipment and allowing the sending exchange station to receive the transmission acknowledgement between the stations to release the retransmission buffer. CONSTITUTION:When an inter-station data packet 6 is received, a reception exchange station 3 generates a data packet 9 and sends it to a reception terminal equipment and sends an inter-station transmission acknowledgement packet 14 to a sending exchange station 2 without awaiting the return of a transmission acknowledgement packet 10 from the reception terminal equipment 4 to the data packet 9 at a point of time 15 automonously. If the reception point of time 16 of the packet 14 is before a time-out of a retransmission timing supervisory timer 12, the transmission exchange station 2 stops the retransmission timing supervisory timer 12, releases a retransmission buffer 7 and abolishes the received packet 14. At time-up, the station 2 retransmits an inter-station data packet 6 whose copy is ensured in the retransmission buffer 7.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] This invention relates to a packet retransmission control system in a packet switching network.

[Conventional technology]

FIG. 2 is a sequence chart showing a conventional packet retransmission control method. In the figure, 1 is a transmitting terminal that transmits data, 2 is a transmitting exchange that accommodates this transmitting terminal 1, and 3 is this transmitting exchange. 2 is a receiving switching center connected thereto, and 4 is a receiving terminal accommodated in this receiving switching center 3. 5 is a transmission data packet of transmission data transmitted from the transmission terminal 1; 6 is an interoffice data packet of processed data transmitted by the transmission switching center 2 which has received and processed the transmission data; 7
is a retransmission buffer that secures a copy of the interoffice data packet 6 within the transmitting exchange 2, 8 is a delivery confirmation packet sent back from the transmitting exchange 2 to the transmitting terminal 1, and 9 is a buffer from the receiving exchange 3. A data packet of data sent to the receiving terminal 4, 10 a delivery confirmation packet sent from the receiving terminal 4 to the receiving switching center 3, and 11 a delivery confirmation packet sent from the receiving switching center 3 to the sending switching center 2. Reference numerals 1) and 12 in the inter-office delivery confirmation packet for delivery confirmation are retransmission timing monitoring timers within the transmitting station, which are activated at time 13 when the inter-office data packet 6 is transmitted.

Next, the operation will be explained. The transmitting switching center 2, which has received the transmit data packet 5 transmitted from the transmitting terminal 1, processes the received transmit data packet 5 to generate an interoffice data packet 6, and holds a copy of it in a retransmission buffer 77. , transmits the interoffice data packet 6 to the receiving exchange 3. Further, the transmitting switching center 2 starts the retransmission timing monitoring timer 12 at the time point 13 of transmitting the inter-office data packet 6, and thereafter starts the retransmission timing monitoring timer 12 at a predetermined timing.
A delivery confirmation packet 8 is sent back to.

Upon receiving the interoffice data packet 6, the receiving switching center 3 generates a data packet 9 and transmits it to a predetermined receiving terminal 4. The receiving terminal 4 that received the data packet 9 transmits the delivery confirmation packet 10 at a predetermined timing, and the receiving switching center 3 that received this sends the interoffice delivery confirmation packet 11.
is generated and sent back to the sending exchange 2. If this interoffice delivery confirmation packet 11 arrives before the retransmission timing monitoring timer 12 times out, the transmitting exchange 2 stops and restores the retransmission timing monitoring timer 12 and secures a copy of the interoffice data packet 6. The retransmission buffer 7 is released, the received inter-office delivery confirmation packet 12 is discarded, and when the retransmission timing monitoring timer 12 times out, the inter-office data packet 6 reserved in the retransmission buffer 7 is discarded.
A copy of the information is sent to the receiving exchange 3.

[Problem that the invention seeks to solve]

Since the conventional packet retransmission control method is configured as described above, from the time the transmitting exchange transmits the processed data to the receiving exchange, the receiving terminal confirms the delivery of the transmitted processed data to the receiving exchange. This often led to problems such as the retransmission buffer being held for a long time for one data communication until the data was returned, and a large retransmission buffer was required.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to obtain a packet retransmission control method that does not require a large retransmission buffer by shortening the holding time of the retransmission buffer.

[Means for solving problems]

In the packet retransmission control method according to the present invention, the receiving switching center automatically performs the inter-office delivery confirmation for sending the data back from the receiving switching center to the sending switching center without waiting until the receiving switching center returns the delivery confirmation from the receiving terminal. This is how it is sent out.

[For production]

The packet retransmission control method according to the present invention releases the retransmission buffer by receiving the inter-office delivery confirmation that the receiving switching center voluntarily sends without waiting for the delivery confirmation from the receiving terminal, and the retransmission buffer holding time is This will significantly shorten the time required for retransmission, thereby making the retransmission buffer more compact.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, 1 to 10 and 12.13 are the same as those indicated by the same reference numerals in FIG. 2, so their explanation will be omitted. Reference numeral 14 indicates that the receiving switching center 3 that has received the interoffice data packet 6 spontaneously sends the data packet 9 without waiting for the return confirmation packet 10 from the receiving terminal 4 in response to the data packet 9.
This is an inter-office delivery confirmation packet for delivery confirmation between offices, and 15 and 16 indicate the time of transmission of this inter-office delivery confirmation packet 14 at the receiving exchange 3 and the time of reception at the sending exchange 2.

Next, the operation will be explained. The process until the receiving switching center 3 receives the inter-office data packet 6 is the same as the conventional case shown in FIG. 2, so the explanation will be omitted.

When receiving the interoffice data packet 6, the receiving exchange 3 generates a data packet 9 and sends it to the receiving terminal 4 in the same way as in the conventional case, and sends a delivery confirmation packet 10 from the receiving terminal 4 to the receiving terminal 4 for this data packet 9. The inter-office delivery confirmation packet 14 is spontaneously transmitted to the sending exchange 2 at time 15 without waiting for the packet to be returned. In the transmitting exchange 2, as in the conventional case, if the reception time 16 of the interoffice delivery confirmation packet 14 is before the retransmission timing monitoring timer 12 times out, the retransmission timing monitoring timer 12 is stopped and the retransmission buffer 7 is opened. It releases and discards the received inter-office delivery confirmation packet 14, and when time is up, it retransmits the inter-office data packet 6 whose copy is secured in the retransmission buffer 7. Here, the delivery confirmation packet 1 that was subsequently returned from the receiving terminal 4
0 is simply discarded at the receiving switching center 3.

〔Effect of the invention〕

As described above, according to the present invention, the receiving exchange voluntarily transmits the inter-office delivery confirmation to be sent back to the sending exchange without waiting for the arrival of the delivery confirmation from the receiving terminal, and the sending exchange Since the retransmission buffer is configured to be released upon receiving a delivery confirmation between packets, the holding time of the retransmission buffer can be significantly shortened and the retransmission buffer can be made smaller. This has the effect of providing a retransmission control method.

[Brief explanation of the drawing]

FIG. 1 is a sequence chart showing a packet retransmission control method according to an embodiment of the present invention, and FIG. 2 is a sequence chart showing a conventional packet retransmission control method. 1 is a sending terminal, 2 is a sending switching center, 3 is a receiving switching center, 4 is a receiving terminal, 5 is a sending data packet, 6 is an interoffice data packet, 7 is a retransmission buffer 7.8° 10 is a delivery confirmation packet, 9 is a data packet, 12 is a retransmission timing monitoring timer, and 14 is an inter-office delivery confirmation packet. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] A packet switching network comprising a transmitting terminal that transmits data, a receiving terminal that receives the data, a transmitting switching center accommodating the transmitting terminal, a receiving switching center connected to the transmitting switching center and accommodating the receiving terminal, etc. In the packet reproduction control method having the above, the transmission switching center, which has received the transmission data transmitted by the transmission terminal, processes the received transmission data, reserves a copy of the processed data in a retransmission buffer, and transfers the processed data. When transmitting the processed data to the receiving switching center, a retransmission timing monitoring timer is started, and a delivery confirmation is sent back to the sending terminal, and the receiving switching center, which has received the processed data, processes the received processed data. It processes it and transmits it to the receiving terminal, and also voluntarily sends back an inter-office delivery confirmation to the sending station without waiting for delivery confirmation from the receiving terminal, and the sending exchange exchanges the inter-office delivery confirmation without waiting for delivery confirmation from the receiving terminal. If the confirmation arrives before the timeout of the retransmission timing monitoring timer, the retransmission buffer in which a copy of the processed data is being secured is released, and if the confirmation has timed out, it is secured in the retransmission buffer. A packet retransmission control method, characterized in that a copy of the processed data is transmitted to the receiving switching center.