JPH09102793A - Repeater system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To store most frames to be received actually in one receiving buffer, and to simplify reception processing so as to enable the high-speed reception processing by changing the size of the receiving buffer to the optimal size on the basis of statistics. SOLUTION: All optimal buffer size calculating device 108 determines the upper limit value of a range in which cumulative ratio reaches definite ratio. A buffer size changing device 107 changes the size of the receiving buffer to the size determined by optimal buffer size calculation. The number of pieces of the receiving buffers becomes the number obtained by dividing the total size of the receiving buffer by the receiving buffer size. Thus, receiving buffer size can be changed. By executing this optimization, the most of the received frames can be stored in one receiving buffer. Thus, the size of the optimized receiving buffer is not too large and not too small for the size of the frame to be received actually, and efficiency becomes best.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relay device having a reception buffer for relaying a reception frame, and more particularly to a relay device capable of optimizing a reception buffer size.

[0002]

2. Description of the Related Art In a conventional relay device, the size of a reception buffer is fixed and cannot be changed.
Usually, the size of the receiving buffer is fixed to the maximum frame length of the local area network to which it is connected, or fixed to a smaller size.

[0003]

The conventional method has the following problems.

(1) If the size of the receive buffer is too small compared to the size of the received frame, multiple buffers must be used to store one frame. Therefore, the receiving process takes time, and the process takes time. For example, if the receive buffer size is 64 bytes and the receive frame size is 4500 bytes,
From 4500 ÷ 64 = 70.3, one frame is 71
Must be stored in separate buffers.

(2) If the size of the reception buffer is too large compared to the size of the reception frame, the free area of the reception buffer becomes large and the efficiency of use of the buffer deteriorates.
Also, compared to the case where the receive buffer size is made smaller,
Since the number of receive buffers that can be secured decreases, the number of frames that can be retained decreases. For this reason, when a large number of frames are received at once, it is not possible to hold all of them and some of the received frames must be discarded. For example, if the receive buffer size is 4500 bytes,
If the received frame size is 64 bytes, only 64 bytes (1.42%) of the 4500-byte buffer will be used. If the total size of the receive buffer is 64 Kbytes, the receive buffer is 65536.
From /4500=14.6, only 14 can be secured.

(3) As shown in (1) and (2) above, if the size of the receiving buffer is too large or too small as compared with the size of the frame to be actually received, the efficiency will be poor. It is desirable to decide according to the size of the received frame. However, the actual frame size to be received varies greatly depending on the type of network to be connected and the method of using the network, so it is impossible to fixedly determine the optimum size.

Therefore, an object of the present invention is to solve the above problems and provide a relay device capable of optimizing the reception buffer size.

[0008]

In order to achieve the above object, the present invention provides a statistical device for obtaining statistical information on a frame size each time a frame is received in a relay device for relaying the frame between a plurality of local area networks. And a changing means for changing the size of the reception buffer to the optimum size based on the statistical information.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The relay device of the present invention comprises statistical means for obtaining statistical information of the frame size each time a frame is received, and changing means for changing the size of the receiving buffer to the optimum size based on the statistical information. Is equipped with.

In the form of statistically measuring the frame size, the range up to the maximum frame size is divided into several ranges, and the number of times the received frames of the corresponding size are generated is accumulated, and this accumulated number is used as a statistical value. Remember. This process is performed every time the relay device receives a frame. Therefore, the number of times the received frame size is generated for each size is statistical information.

The mode for changing the size of the reception buffer is as follows.
The reception buffer size is calculated so that most of the frames received so far can fit in one reception buffer, and the size of the reception buffer is changed to that size. As a result, it can be expected that the majority of frames to be received in the future will fit in one reception buffer. Received frames of a larger size will be stored separately in a plurality of receive buffers, but it can be determined that the occurrence is statistically small. Therefore,
Reception processing time is shortened. In addition, the size of the receive buffer does not unnecessarily increase, so the free area is reduced. Therefore, the use efficiency of the buffer is improved.

Specific embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the relay apparatus according to the present invention has a network interface 106 connected to a plurality of local area networks, a receiving unit 105, and a main memory 102, and the main memory 102 receives the data. It has a buffer area 103. Further, as a statistic means for obtaining the statistic information of the received frame each time the frame is received, the statistic information storage area 104 is provided in the main memory 102, and the changing means for changing the size of the receiving buffer to the optimum size based on the statistic information. It has an optimum buffer size calculating means 108 and a buffer size changing means 107.

An example of the structure of the receiving buffer is shown in FIG. A plurality of reception buffers 203 are secured in the reception buffer area 103 (in the illustrated example, there are four buffers 1 to 4, but any number may be used). Each reception buffer 203 is provided with a buffer descriptor 202 in which information about a frame, a buffer size, a buffer start address, and the like are set, and all the buffer descriptors 202 are chained in a ring shape. That is, descriptor 1 has descriptor 2
The index information of is attached, the descriptor 2 is attached with the index information of the descriptor 3, and the like. Further, the head pointer 201 points to the head descriptor. In this receiving buffer configuration, the descriptor has the buffer size and the buffer start address, so the buffer size can be arbitrarily changed.

The total size of the receive buffer is 64 Kbytes.

An example of the structure of the statistical information storage area 104 is shown in FIG. In this example, the maximum frame size is assumed to be 4500 bytes, and the maximum frame size is 0 to 450 bytes.
A frame size column 301 is provided in a range of 450-byte intervals such as 450 to 900 bytes. Then, a column 302 for the number of received frames of a corresponding size is provided for each range. The operation of the statistical information storage area 104 is such that when the receiving unit 105 receives a frame from the network interface 106 and stores the frame in the reception buffer, the reception number in the column corresponding to the size of the reception frame is incremented by one. .

An actual operation example will be described.

FIG. 4 shows an example of statistical information stored in the statistical information storage area 104 in a graph format. The vertical axis of this graph is the ratio of the number of receptions for each range to the total number of reception frames.
From this figure, it can be seen that a large number of received frames with a frame size of 450 to 900 bytes or close thereto are generated, and large received frames close to 4500 bytes are rarely generated.

In order to calculate the optimum buffer size, the statistical information is processed into statistical information which is sequentially accumulated from the smaller size to the larger size. As a result of the processing, FIG. 5 shows a graph in which the vertical axis represents the cumulative ratio with respect to the total number of received frames. In this figure, a line with a cumulative ratio of 80% is indicated by a broken line. From this figure, most frames are 0-2
It turns out that it fits in the range of 250 bytes.

The optimum buffer size calculating means has an upper limit value (225) of a range (in this example, a range of 1800 to 2250 bytes) in which the cumulative ratio reaches a constant ratio (for example, 80%).
0 bytes). The buffer size changing means changes the size of the receiving buffer to the size (2250 bytes) obtained by the optimum buffer size calculating means. The number of reception buffers is the total size of the reception buffers divided by the reception buffer size (65536/2250 = 29 from 29. 1). By doing so, the receive buffer size can be changed without changing the total size of the receive buffer.

By performing the above optimization, most of the received frames (80% or more in this example) can be stored in one receiving buffer. In this way, the size of the receiving buffer optimized based on the statistics is not too large or too small as compared with the size of the actually received frame, and is the most efficient.

[0022]

The present invention exhibits the following excellent effects.

(1) Since the size of the receiving buffer is changed to the optimum size based on statistics, most of the frames actually received can be accommodated in one receiving buffer, and the receiving process is simplified. The reception process can be performed at high speed.

(2) Since the size of the receiving buffer is changed to the optimum size based on statistics, it becomes possible to determine the receiving buffer size in accordance with most of the frame size actually received. It is possible to reduce the empty area of the and improve the usage efficiency.

(3) Since the size of the receiving buffer is changed to the optimum size based on statistics, the optimum size can be determined regardless of the type of network to be connected or the method of using the network.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of a relay device of the present invention.

FIG. 2 is a configuration diagram of a reception buffer of the present invention.

FIG. 3 is a configuration diagram of a statistical information storage area of the present invention.

FIG. 4 is a statistical chart showing a ratio of the number of received frames for each range to the total number of received frames as an example of statistical information according to the present invention.

FIG. 5 is a statistical chart showing an example of statistical information according to the present invention, showing a cumulative ratio of the number of received frames in order of decreasing size to the total number of received frames.

[Explanation of symbols]

 103 receive buffer area 104 statistical information storage area 107 buffer size changing means 108 optimum buffer size calculating means 203 receive buffer

Claims (1)

[Claims] 1. In a relay device for relaying a frame between a plurality of local area networks, statistical means for obtaining statistical information of the frame size each time the frame is received, and an optimum size of a receiving buffer based on the statistical information. A relay device comprising: a changing unit configured to change to.