JPS61172459A - Packet exchange network - Google Patents

Abstract

PURPOSE:To control steadily a processing load of a packet exchange at transmission side and reception side by setting a packet composing timing of a packet composing/decomposing device in response to flow control information. CONSTITUTION:When the own station or the packet composing/decomposing device 2b connected to the own station is in congestion and a packet is not received any more, a packet exchange 1b sends an RNR packet [flow control packet 10] to a packet exchange at transmission side from a flow control means. When the congesting state at the reception side is eliminated and the reception of the packet is desired to restart, an RR packet [flow control packet 10] is sent to a packet exchange at transmission side. After the RNR or RR flow control packet 10 is received by a packet exchange 1a, the packet is stored in a flow information means 11 as flow control information. The flow control information is transmitted to the packet composing/decomposing device 2a by a flow informing means 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a packet switching network in which terminal devices assemble packets and communicate with each other, and a 4IK packet assembling method.

[Conventional technology]

Conventionally, in this type of packet switching network, data input from a terminal device to a packet assembly/disassembly device is sent to a bucket) K assembly [
Since the assembling timing is fixed, the packet assembling and disassembling device divides the input data into multiple packets of a fixed length, regardless of the reception status of the packet switching device on the receiving side connected via the trunk line. The data was divided into multiple packets by adding necessary packet information to each divided data. Therefore, the number of packets to be assembled is uniquely determined by the amount of input data.

[Problem that the invention seeks to solve]

In this way, in conventional packet switching networks, the timing at which the packet assembling and disassembling device packetizes data input from the terminal device is unrelated to the reception status of the packet switching device on the receiving side via the trunk line, and When the packet switching equipment on the sending side is busy, packets are sent out even when the equipment is busy, but because these packets cannot be accepted, the number of packets that must be sent to the buffer in the sending packet switching equipment increases. There is a problem in that packets may even be discarded, and if an attempt is made to improve this problem, there is also a problem in that the processing load on the packet switching device on the transmitting side increases rapidly.

This invention was made in order to eliminate the above-mentioned problems, and the packet switching device on the receiving side transmits flow rate control information according to the congestion state of its own station or the packet assembling and disassembling device connected to its own station. The timing for assembling packets is set according to this flow rate control information, and the timing for assembling packets is set longer when the packet switching equipment on the receiving side is unable to receive packets due to congestion. To obtain a packet switching network that can reduce the number of packets sent per unit time from a packet assembly/disassembly device on the sending side to a packet switching device on the receiving side, and reduce an increase in processing load in the packet switching device on the sending side. It is intended for this purpose.

[Means for deciding issues]

In the packet switching network according to the present invention, when the packet assembling and disassembling device packetizes the input data received from the packet terminal device, the packet assembling and disassembling device packetizes the timing according to the congestion state of the packet switching device on the receiving side. In other words, it is possible to determine the period.

[Effect]

The packet switching network in this invention controls the flow rate of the packet switching network in order to generate packets according to the congestion state of the destination packet switching device and the packet assembly/disassembly device, and also controls the packet switching device on the sending side and the receiving side. The processing load is constantly controlled.

〔Example〕

Hereinafter, one embodiment of the present invention will be explained with reference to the figures.
The figure is a block diagram showing the configuration of a packet switching network using a packet assembly method, which is an embodiment of the present invention.

In FIG. 1, 1a and 1b are packet switching devices on the transmitting side and receiving side, respectively; 2a and 2b are packet assembling and disassembling devices on the transmitting side and receiving side, respectively; 3a and 3b are terminal devices on the transmitting side and receiving side, respectively; 4 is a trunk line, 5 is data input from the terminal device 3a to the packet assembling and disassembling device 2aK, 6 is a packet from which this data 5 is assembled by the packet assembling and disassembling device 2a and sent to the packet switching device 1a, and 7 is a certain packet exchange A packet is transmitted from the device 1a to another packet switching device 1bK via the trunk line 4, 8 is a packet sent from the packet switching device 1b to the packet assembling and disassembling device 2b, and 9 is a packet that is disassembled by the packet assembling and disassembling device 2b. This data is generated and sent to the terminal device 3bK.

When the terminal devices 3a and 3b communicate with each other, data 5 input from the terminal device 3a is packetized at a certain period (packet assembly timing) by the packet assembling and disassembling device 2aK. This packet 6 is sent to the packet switching device 1a.
The data is sent to the packet switching device 1bK on the other side, that is, the receiving side, via the trunk line 4, and is received if the packet switching device 1b on the other side is capable of receiving the data. Thereafter, the received packet is sent to the packet assembling and disassembling device 2b, decomposed into data 9, and output to the destination terminal device 3b.

FIG. 2 is a block diagram for explaining the relationship among the flow rate control packet 10, the flow rate control means 14, and the flow rate notification means 11. When the packet switching device 1b on the receiving side or the packet assembling/disassembling device 2b connected to the local station becomes congested and cannot receive any more packets or when it is desired to reduce the number of packets to be received, the packet switching device 1b on the receiving side RN R (Receiving) from the flow rate control means of the packet switching device 1b.
e Not Ready) packet [flow rate control packet 10] is sent to the packet switching device on the receiving side. After that, when the congestion condition on the receiving side is resolved and you want to resume receiving packets or increase the number of packets to be received,
An RR (Receive Ready) packet [flow rate control packet 10] is sent to the transmitting side packet switching device.

After these RNR or RR flow rate control packets 10 are received by the packet switching device 1a, the flow rate notification means 11
is stored as flow rate control information. This flow rate control information is transmitted to the packet assembling and disassembling device 22 by the flow rate notification means 11.

FIG. 3 is a state diagram showing the flow rate control information by the flow rate notification means 11 in the packet switching device 1a, the packet assembly timing table 13 and the current pointer value 12 in the packet assembling and disassembling device 2a.

The pointer value of the packet assembly timing table 13 is 0.
It is an integer value from ~n, and the pointer value 0 to n is 1:
Packet assembly timing T corresponds to 1. ~Tn exists, and the packet assembly timing increases as the pointer value increases. As the packet assembling timing increases, the number of packets assembled per unit time by the packet assembling and disassembling device 2a decreases.
The number of packets transmitted from a to the packet switching device 18 per unit time decreases. The current pointer value 12 points to any pointer value from O to n in the packet assembly timing table 13.

The pointer value determines the current packet assembly timing.

FIG. 4 is a flow diagram showing a process in which the packet disassembly device 2a on the transmitting side changes the packet assembly timing in the packet assembling and disassembling device 2a based on the flow rate control information sent from the packet switching device 1b on the receiving side. Processing differs depending on whether the flow rate control information is RR or RNR; in the case of RNR, the packet switching device 1b on the receiving side expects a decrease in the packet generation rate on the transmitting side, so the current pointer value 12 is incremented. . However, if the current pointer value 12 is the maximum value n of the pointer values in the packet assembly timing table 13, no processing is performed. Also, R
In the case of R, the congestion condition of the destination packet switching device is alleviated and it is possible to receive the sufficient number of packets per unit time that are currently being generated, so the current pointer value 12 is decremented and the packet generation rate is increase.

However, if the current pointer value 12 is the minimum value O, no decrement is performed.

〔Effect of the invention〕

As described above, according to the present invention, in a packet switching network, a flow rate control means for controlling the flow rate of packets and a flow rate notification means for notifying the flow rate control information from the flow rate control means are provided, and the flow rate control information is - Since the packet assembling timing of the packet assembling and disassembling device is set according to the information, the number of packets assembled per unit time by the packet assembling and disassembling device on the transmitting side can be adjusted according to the congestion state of the packet switching device on the receiving side. This has the effect of providing a packet switching network that can reduce the increase in processing load within packet switching devices on the sending and receiving sides.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a packet switching network showing an embodiment of the present invention, FIG. 2 is a block diagram illustrating the flow of flow rate control information in FIG. 1, and FIG.
FIG. 4 is a state diagram for explaining the assembly timing table of the packet assembly/disassembly device 2a shown in the figure, and FIG. 4 is a flow diagram showing the flow of FIG. 3. In the figure, 1a and 1b are packet switching devices, 2a,
2b is a packet assembly and disassembly device, 3a and 3b are terminal devices, 4 is a trunk line, 5.9 is data, 6 to 8 are packets, 1
0 is a flow rate control packet (flow rate control information), 11 is a flow rate notification means, and 14 is a flow rate control means. In each figure, the same reference numerals indicate the same or corresponding parts. Patent applicant: Mitsubishi Electric Corporation (Continued from page 1) Inventor: Saka-Sachi 3 Kamimachiya, Kamakura City
2. Mitsubishi Electric Corporation Information and Electronics Research Laboratory Procedures Amendment (Voluntary)

Claims (1)

[Claims] A plurality of packet switching devices connected by trunk lines, a plurality of terminal devices connected to the packet switching device, and a plurality of terminal devices connected between the packet switching device and the terminal device and packetizing input data from the terminal device. Communication is performed between the terminal devices in a packet switching network comprising a packet assembling and disassembling device that transmits data to the packet switching device, disassembles packets received from the packet switching device, and outputs data to the terminal device. In this case, even though input data from a certain terminal device is packetized by the packet assembling and disassembling device, transmitted to the packet switching device, and sent to the receiving side packet switching device via the trunk line, First, to control the timing of assembling packets on the sending side when the packet switching device is not receiving packets due to congestion, or when it is confirmed that packets sent after the above packets may not be received. The packet switching device on the sending side sends the information to the flow rate control means provided in the packet switching device on the receiving side, and notifies the packet assembly and disassembly device on the receiving side of the flow rate control information sent from this flow rate control means. and a packet assembling and disassembling device that determines the timing for packetizing data from the terminal device based on the flow rate control information notified from the flow rate notification means. packet-switched network.