JPH0758806A - Packet communications system - Google Patents

Abstract

PURPOSE:To select an optimum packet length depending on a reception buffer capacity by providing a packet length decision section so as to decide an optimum packet length within the capacity of a reception buffer among packet length data in a memory. CONSTITUTION:Data representing a packet length from length 1 till length (n) are stored in a memory 20, and data representing a maximum packet length and data representing a minimum packet length are stored in a transmission line packet length storage section 24. After recognizing the capacity of a reception buffer 11, a packet length decision section 22 picks up packet length data whose capacity is less than that of the buffer 11 among packet length data stored in the memory 20. Then the section 22 picks up packet length data within a maximum packet length and a minimum packet length stored in the storage section 24 and decides a maximum packet length so that the capacity is one over an integral number of the capacity of the buffer 11 among the picked up data and sends the decided data to a transmission section 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication system, and more particularly to a packet communication system which can always perform data communication with an optimum packet length.

[0002]

2. Description of the Related Art FIG. 4 is a conceptual diagram of a conventional packet communication system. In the figure, 10 is a communication device connected to each other via a bidirectional transmission path 1. Reference numeral 11 is a reception buffer provided in the communication device 10 for receiving packet data. The capacity of the receiving buffer 11 is, for example, about several kilobytes. 3 is a packet transmitted on the transmission path. A packet having a length of several kilobytes is used. Reference numeral 2 is a storage device for data storage connected to the communication device 10.

In the thus configured packet communication system, consider a case where data is transmitted from the communication device # 1 in the figure to the communication device 10 # 2. The packet data transmitted from the # 1 communication device 10 is temporarily held in the reception buffer 11 in the # 2 communication device 10. While being held, the # 2 communication device 10 checks the ID of the header of the packet to see if the data is addressed to itself and if the received data is error-free. When the data is addressed to itself and the data is normal, the communication device 10 performs necessary processing and accumulates the data in the storage device 2.

[0004]

In the above-described conventional system, each communication device 10 packetizes the data to be transmitted and communicates. At this time, the packet length is packetized within the maximum packet length allowed by the transmission path 1. Had to do. In this packetization, if the data length exceeds the maximum packet length allowed by the transmission line 1, the data is packetized and transmitted at the maximum packet length of the transmission line 1. Further, at this time, in determining the packet length, the receiving communication device 10
The capacity of the receiving buffer 11 of 1 was not taken into consideration.

Therefore, since the packet length is determined by the maximum packet length allowed by the transmission path 1, there is a problem that the receiving side may overflow the receiving buffer 11 and drop the packet. Further, when the maximum packet length allowed by the transmission line 1 becomes large with the improvement in the capacity of the transmission line 1, it becomes possible to transmit more than the capacity of the reception buffer 11, so that there is a problem that the packet cannot be received. .

The present invention has been made in view of the above problems, and an object thereof is to provide a packet communication system capable of selecting an optimum packet length according to the capacity of a reception buffer.

[0007]

FIG. 1 is a block diagram of the principle of the present invention, showing the configuration of a receiving section of a communication device. Figure 4
The same parts as those shown in FIG. The system shown in the figure constitutes a system in which communication devices 10 perform packet communication with each other via a transmission line 1. Reference numeral 11 is a reception buffer for receiving packet data from the partner communication device 10, 20 is a memory for storing a plurality of communicable packet length data, and 22 is the capacity of the reception buffer 11 and the memory 2.
A packet length determination unit that determines the packet length from the packet length data stored in 0, and a transmission unit 23 that transmits the packet length data determined by the packet length determination unit 22 to the transmission side. Reference numeral 24 denotes a transmission path packet length storage unit that stores the maximum packet length data and the minimum packet length data that can be transmitted by the transmission path 1 being used, and 4 is an interface (INT) that connects the transmission path 1 and a communication device. .

[0008]

After checking the capacity of the receiving buffer 11, the packet length determining unit 22 selects the optimum packet length within the capacity of the receiving buffer 11 from the packet length data stored in the memory 20. Then, the transmitting unit 23 notifies the partner transmitting unit. As described above, according to the present invention, the optimum packet length can be selected according to the capacity of the reception buffer.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, the present invention will be described in detail with reference to the principle diagram of FIG. The memory 20 stores data indicating the packet lengths from the packet length 1 to the packet length n as shown in the figure. On the other hand, the transmission path packet length storage unit 24 stores data indicating the maximum packet length that can be transmitted on the transmission path 1 and data indicating the minimum packet length.

First, the packet length determination unit 22 knows the capacity of the reception buffer 11. Next, the packet length determination unit 22
Selects from the packet length data stored in the memory 20, the packet length data that is less than or equal to the capacity of the reception buffer 11. Next, the transmission path packet length storage unit 24
The maximum packet length and minimum packet length data stored in is read, and the packet length data within the maximum packet length and the minimum packet length is picked up from the packet length data read from the memory 20. Next, the reception buffer 11 is selected from the picked-up packet length data.
The maximum packet length is determined so that it is an integer fraction of the capacity.

The packet length determination unit 22 sends the determined packet length data to the transmission unit 23. The transmission unit 23 transmits the input packet length data via the interface 4 to the transmission line 1
Is transmitted to the transmission side communication device 10 via.

The transmitting side communication device 10 is the receiving side communication device 1.
The transmission data is packetized using the packet length received from 0 and transmitted to the receiving side communication device 10 via the transmission line 1. On the receiving side, the received data is stored in the storage device 2 (see FIG.
Sequentially store in ().

FIG. 2 is a block diagram showing the configuration of an embodiment of the transmitting section of the communication device according to the present invention. The same parts as those in FIGS. 1 and 4 are designated by the same reference numerals. When packet length data is sent from the receiving side communication device 10 via the transmission line 1 and the interface 4, it enters the data receiving unit 30.

The packet length determining unit 31 is used by the data receiving unit 3
The packet length data held at 0 is read, the packet length is determined, and the packet length is sent to the packet creation unit 32. The packet creating unit 32 divides the data stored in the storage device 2 into packets by the determined packet length and sends the packets to the data transmitting unit 33. The data transmitting unit 33 sequentially transmits the incoming packet data from the transmission line 1 to the receiving communication device 10 via the interface 4.

FIG. 3 is a diagram showing the operation of the present invention. In this embodiment, from the maximum packet length and the minimum packet length allowed by the transmission path 1 (stored in the transmission path packet length storage unit 24 of FIG. 1) in advance on the receiving side, for example, from the packet length 1 as shown in the figure. The packet length is determined in 5 steps up to the packet length 5.

After the capacity of the receiving buffer 11 is checked (S1), the receiving-side packet length determining unit 22 determines the maximum packet length of the packet length data stored in the memory 20, which facilitates buffer management ( S2). When the maximum packet length is determined, the transmission unit 23 notifies the transmission side communication device 10 of the packet length data via the interface 4 and the transmission path 1 (S3).

On the transmitting side, when the packet length data sent from the receiving side communication device 10 is recognized, the packet creating section 32 packetizes the data stored in the storage device 2 with the given maximum packet length (S4). ), And sends it to the data transmission unit 33. The data transmitter 33 starts transmitting the packet data via the interface and the transmission line 1 (S5).

When it is necessary to change the maximum packet length during transmission of packet data, the receiving-side packet length determining unit 22 selects the necessary packet length from the packet length data stored in the memory 20. The long data is read, and the changed maximum packet length data is notified to the transmission side communication device 10 via the transmission unit 23. Transmission side communication device 1
At 0, thereafter, the packet length data to be transmitted is changed to the changed packet length and the data is transmitted. Thereby, the packet length can be dynamically changed.

As described above, according to the present invention, since the maximum packet length can be selected, the receiving side can maximize the buffer capacity without waste, increase the number of received packets, and facilitate buffer management. You can do it. Further, since the receiving side can determine the packet length sent from the transmitting side by the receiving side, it is possible to reduce the frequency of dropped packets due to overflow of the buffer by performing allocation in advance. Also, the packet length can be notified from the transmitting side to the receiving side. As a result, the frequency of packet retransmission can be reduced, and the throughput of data communication can be improved.

[0020]

As described above in detail, according to the present invention, it is possible to provide the packet communication system capable of selecting the optimum packet length according to the capacity of the receiving buffer.

[Brief description of drawings]

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

FIG. 2 is a configuration block diagram showing an example of a transmission unit.

FIG. 3 is a diagram showing an operation of the present invention.

FIG. 4 is a conceptual diagram of a communication system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 transmission line 4 interface 11 reception buffer 20 memory 22 packet length determination unit 23 transmission unit 24 transmission line packet length storage unit

Claims (4)

[Claims] 1. In a system in which a communication device (10) performs packet communication with each other via a transmission line (1), a receiving unit of each communication device (10) has a reception buffer (receiver buffer for receiving packet data from a partner communication device). 11), a memory (20) for storing a plurality of communicable packet length data, and a packet length determination for determining the packet length from the capacity of the reception buffer (11) and the packet length data stored in the memory (20). A packet communication system comprising a section (22) and a transmission section (23) for transmitting the packet length data determined by the packet length determination section (22) to a transmission side. 2. The packet length determination unit (22) includes a capacity of the reception buffer (11), a plurality of packet lengths stored in the memory (20), and a maximum transmission packet length of a transmission path stored in advance. The optimum packet length is determined from the minimum transmission packet length.
The described packet communication system. 3. The packet length determination unit (22) dynamically changes the maximum packet length from the packet length data stored in the memory (20) as needed while the receiving side is receiving data. The packet communication system according to claim 1, wherein 4. In a system in which communication devices (10) perform packet communication with each other via a transmission line (1), a transmission section of each communication device (10) holds packet length data sent from a transmission side. And a packet length determining unit (31) for receiving the output of the data receiving unit (30) and determining the packet length, and a packet creation for packetizing the transmission data with the determined packet length. The packet communication system according to claim 1, comprising a unit (32) and a data transmission unit (33) for transmitting the packet data sent from the packet creation unit (32).