JPH0241222B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packet assembly method for mutually communicating data between a plurality of terminal devices in a packet switching network.

[Conventional technology]

Conventionally, in a terminal device on the sending side, data is
A packet switching method is known in which a packet containing destination information and other control information necessary for data transfer is divided and transferred in units of packets to a terminal device on the other side via a packet switching device. The packet switching network in which this packet switching method is implemented consists of multiple packet switching devices connected to trunk lines, multiple terminal devices connected to the packet switching devices, and networks between the packet switching devices and the terminal devices. Then, the data input from this terminal device is converted into packets and transmitted to the packet switching device, and
The packet assembling and disassembling device disassembles the packets received from the packet switching device and outputs the data to the terminal device.

[Problem that the invention seeks to solve]

In the packet assembling method in the conventional packet switching network as described above, the timing at which the packet assembling and disassembling device converts data input from a terminal device into packets is determined by the timing at which the packet assembling and disassembling device is connected via a trunk line. This was determined regardless of the receiving status of the packet switching equipment on the other side. Therefore, when the other party's packet switching device is congested, packets cannot be accepted, and the number of packets that must be transmitted increases in the buffer in the sending packet switching device. As a result, a problem arises in that the processing load within the packet switching device on the sending side tends to increase rapidly.

The present invention was made to solve this problem, and aims to provide a packet assembly method that can regulate the number of packets input to a packet switching network depending on the congestion state of the packet switching network. This is the purpose.

[Means for solving problems]

The packet assembly method according to the present invention, when the other party's packet switching device is in a congested state,
The timing at which the packet assembling and disassembling device packetizes data input from a terminal device is changed depending on the number of retransmissions performed by the packet switching device on the sending side.

[Effect]

In the packet assembly method of this invention,
By setting the timing at which the packet assembling and disassembling device converts the data input from the terminal device into packets according to the number of retransmissions per packet, which changes depending on the reception status of the packet switching device on the other side, the packet on the other side can be When the switching device is congested and cannot receive packets, the timing for assembling packets is lengthened to reduce the number of packets sent per unit time from the packet assembling and disassembling device on the sending side to the packet switching device on the sending side, To reduce the increase in processing load within a packet switching device on the sending side.

〔Example〕

FIG. 1 is a block diagram showing a packet switching network using a packet assembly method, which is an embodiment of the present invention. In the figure, 1 is a packet switching device, 2 is a packet assembling and disassembling device, 3 is a terminal device, 4 is a trunk line, 5 is data input from the terminal device 3 to the packet assembling and disassembling device 2, and 6
7 are assembled by the packet assembling and disassembling device 2 and sent to the packet switching device 1.
8 is a packet sent from a packet switching device 1 to another packet switching device 1 via the trunk line 4, 8 is a packet sent from the packet switching device 1 to the packet assembling and disassembling device 2, and 9 is a packet assembling and disassembling device. This data is generated by disassembling a packet in the device 2 and sent to the terminal device 3.

In the packet switching network configured as shown in FIG. 1 above, when the terminal devices 3 communicate with each other, the data 5 input from the terminal devices 3
are packetized at a certain period (packet assembly timing) by the packet assembly/disassembly device 2. Packet 6 packetized in this way
is sent to the packet switching device 1, and transmitted as a packet 7 via the trunk line 4 to the other party's packet switching device 1, and is received if the other party's packet switching device 1 is in a receivable state. Thereafter, the packet 8 is sent from the other party's packet switching device 1 to the packet assembling and disassembling device 2, and the packet assembling and disassembling device 2 converts the packet 8 into data 9.
The data is decomposed into two parts and output to the destination terminal device 3.
Here, if the packet 7 cannot be received by the packet switching device 1 on the other side, the packet switching device 1 on the sending side retransmits the same packet 7 via the trunk line 4 after a certain period of time.

Figure 2 shows that in the packet switching network of Figure 1,
FIG. 3 is a diagram showing the number of retransmissions in the packet switching device, the packet assembly timing table in the packet assembling and disassembling device, and the current pointer value. As shown in the figure, the pointer values of the packet assembly timing table 12 are integer values from 0 to n, and packet assembly timings To to Tn exist in 1:1 correspondence to the pointer values 0 to n. The packet assembly timing To to Tn increases as the pointer value 0 to n increases. As the packet assembly timing To~Tn increases,
Since the number of packets assembled by the packet assembling and disassembling device 2 per unit time decreases, the number of packets transmitted from the packet assembling and disassembling device 2 to the packet switching device 1 per unit time decreases. The current pointer value 11 points to any pointer value from 0 to n in the packet assembly timing table 12. The pointer value determines the current packet assembly timing.

Figure 3 shows that in the packet switching network of Figure 1,
This is a flowchart for explaining the process of changing the number of retransmissions and packet assembly timing according to the content of the response from the other party's packet switching device after transmitting a packet. FIG. 3 shows that after the packet switching device 1 on the sending side transmits a packet, the packet switching device 1 on the other side that received the packet
This is a flowchart of a process for changing the packet assembly timing in the packet assembly/disassembly device 2 on the transmitting side depending on the content of the response from the sender. In other words, after a packet is sent, processing may be delayed depending on whether the packet is received by the other party's packet switching device 1 or not received due to congestion in the other party's packet switching device 1, depending on the content of the response. Divided. If it is not received, retransmission is performed, so the number of retransmissions is incremented by 10. If received, the number of retransmissions 10 is reset to the initial value 0. Next, determine the number of retransmissions 10, and if the number of retransmissions 10 is not the initial value 0,
Considering that the packet switching device 1 on the other side continues to be in a congested state, and therefore the transmitted packets are not received and are retransmitted, the number of retransmissions 10 is incremented, and in order to increase the packet assembly timing, Increment the current pointer value 11. However, when the current pointer value 11 is the maximum value n of the pointer values in the packet assembly timing table 12, nothing is done. If the number of retransmissions 10 is the initial value 0,
Considering that the congestion condition of the packet switching device 1 on the other side has been alleviated and the transmitted packet has been received, the number of retransmissions 10 has been reset to the initial value 0.
In order to reduce the packet assembly timing in the packet assembly/disassembly device 2, the current pointer value 11 is decremented. However, if the current pointer value 11 is the minimum value 0, nothing is done.

Through the above processing, the number of packets assembled per unit time by the packet assembling and disassembling device 2 on the sending side can be changed according to the congestion state of the packet switching device 1 on the sending side. It is possible to prevent an increase in the number of packets in one buffer.

〔Effect of the invention〕

As explained above, in the packet assembly method, when the other party's packet switching device is in a congested state, the packet assembling and disassembling device adjusts the timing at which data input from the terminal device is converted into packets by the transmitting side packet switching device. I made it change depending on the number of retransmissions performed, so
Depending on the congestion state of the packet switching network, the number of packets sent per unit time from the packet assembling and disassembling device on the sending side to the packet switching device on the sending side is reduced, thereby reducing the increase in the processing load within the packet switching device on the sending side. This has the excellent effect of being able to effectively reduce the amount of water.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing a packet switching network using a packet assembly method which is an embodiment of the present invention, and FIG. 2 shows the number of retransmissions in the packet switching device in the packet switching network of FIG. A diagram showing a packet assembly timing table and current pointer values in the packet assembly and disassembly device;
FIG. 3 is a flowchart for explaining the process of changing the number of retransmissions and packet assembly timing in the packet switching network shown in FIG. be. In the figure, 1... packet switching device, 2...
Packet assembly and disassembly device, 3...terminal device, 4
...Relay line, 5,9...Data, 6,7,8...
Packet, 10... Number of retransmissions, 11... Current pointer value, 12... Packet assembly timing table. In each figure, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1 A plurality of packet switching devices connected to a trunk line, a plurality of terminal devices connected to the packet switching devices, and a device existing between the packet switching device and the terminal device, and transmitting data input from the terminal devices into packets. In a packet switching network consisting of a packet assembling and disassembling device that converts the packets into packets and transmits them to the packet switching device, and disassembles the packets received from the packet switching device and outputs the data to the terminal device, When performing communication, data input from the terminal device is converted into packets by the packet assembling and disassembling device, and the packet is transmitted to the packet switching device, and the packet assembling and disassembling device is connected via the trunk line. means for notifying the packet assembling and disassembling device of the number of times the packet is retransmitted by the packet switching device that sent the packet when the packet is not received by the packet switching device even though the packet is sent to the packet switching device; A packet assembly method characterized by comprising timing determining means for extending the interval at which the packet assembly and disassembly device packetizes data input from the terminal device when the number of retransmissions is large.