JPS63222549A - Reception buffer management equipment - Google Patents

Abstract

PURPOSE:To use a buffer while packing its memory from its end by discriminating the necessity of a received frame and resetting the address generating circuit designating the address of the reception buffer to be restored in case of an undesired frame. CONSTITUTION:A sequence circuit 4 selects the 1st buffer 5 and the 2nd buffer 7 alternately for each reception frame and gives a signal to corresponding address generating circuits 6, 8. The address generating circuit gives an address to each buffer and stores a reception frame. A discrimination controller 9 reads a control information area written in a specific location of the reception frame from the buffer received just now and gives a reset signal to the corresponding address generator 6 or 8 when an unrequired frame is discriminated. The address generation circuit restores the address counter for write to a value before the unrequired frame is received to prepare the reception of the succeeding frame. Thus, only the required frame is stored continuously in the area at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a reception buffer management device, and particularly to a reception buffer management device in a reception section of a communication device.

[Conventional technology]

In a receiving unit of a communication device, a received frame coming from a transmission path is first stored in a receiving buffer. Since the buffer has a finite length and frames that cannot be stored in the buffer are discarded, it is important to use the buffer efficiently. A normal receiving device determines whether the frame needs to be received online before buffering it.
Therefore, only the frames that need to be received are stored in the buffer. In addition, since the received frames are generally processed in the order in which they are received, the empty area is always a continuous area. Conventional buffer management methods assume such a case.

However, in connection devices that connect multiple communication networks, it is generally difficult to determine in real time whether or not a frame needs to be received, so the determination is often made after all frames have been stored in a buffer. In such a case, the buffer area in which frames that are found to be unnecessary can be used for the next frame in the same way as free space, but these will be distributed in the buffer area. , conventional methods cannot perform efficient buffer management.

The first conventional method is to sequentially store data from the edge of the buffer.Buffer management is simple, and all you have to do is advance the counter. A second conventional method is a method in which the buffer area is divided into small areas and connections between these small areas can be set freely, and is called a data chaining method.

[Problem that the invention seeks to solve]

In the first conventional method described above, the frames can only be used in order from the edge to the edge. Therefore, even if a frame is known to be unnecessary, a necessary frame that has not yet been processed is stored before it. If the unnecessary frames are stored, the buffer area in which the unnecessary frames are stored cannot be used, resulting in poor efficiency. Also, the conventional second
According to the method, even if the free space is distributed 5,
Since the occupied areas can be skipped and the empty areas can be used by connecting them, there is no waste as in the first method. However, 1 - In this second method, if there are gaps due to frequent reception of unnecessary frames, the buffer area will be gradually fragmented, and management of the connections between the fragmented areas will become very complicated. The problem is that it is expected that this will happen.

[Means for solving problems]

The present invention divides a buffer for storing received frames into multiple areas, stores the received frames alternately in the multiple buffer areas, and determines which frames have already been received while the received frames are being received in other buffer areas. If the received frame is an unnecessary frame, the address counter that specifies the address of the receive buffer is reset to the original value, allowing both buffers to store the necessary frames in order. It is a management device.

A reception buffer management device of the present invention includes, in a reception unit of a communication device, a buffer divided into a plurality of areas for storing received frames, an address generation circuit that specifies write and read addresses for the plurality of buffer areas, A sequential circuit inputs a reception signal indicating frame reception from a reception control device and sequentially stores the received frames in the plurality of buffer areas, and a sequential circuit that determines whether already received frames are necessary or unnecessary, and stores unnecessary frames if they are unnecessary. If so, the present invention is characterized by comprising a determination control device which instructs resetting of the address generation circuit to designate the address of the reception buffer.

〔Example〕

Next, embodiments of the present invention will be described using the drawings.

FIG. 1 is a block diagram showing an embodiment of the reception buffer management device of the present invention, in which the buffer is divided into two areas. In FIG. 1, 1 is a reception control device, and 2 is a reception buffer management device. A reception control device 1 takes in information frames on a transmission path, sends them onto a data bus 3, and outputs a reception signal. The sequential circuit 4 alternately selects the first buffer 5 and the second buffer 7 for each received frame and outputs signals to the corresponding address generation circuits 6 and 8, respectively. Address generation circuit 6 specified by sequential circuit 4
or 8 gives an address to each buffer 5 or 7 to store the received frame. The reception control device 1 indicates the end of reception.
The sequential circuit 4 learned from the received signal from the discrimination control bag W
9 to make a determination. The determination control device 9 reads the control information area written at a specific position of the received frame from the buffer that has just been received, and determines whether the frame needs to be received. As a result of the determination, if the frame is found to be unnecessary, the determination control device 9 issues a reset signal to the corresponding address generator 6 or 8. Upon receiving the reset signal, the address generation circuit returns a write address counter (not shown) to the value before receiving this unnecessary frame and prepares for reception of the next frame. Each time one frame of these operations is received,
Furthermore, if you do this within the minimum frame reception time, even if you receive multiple frames consecutively, the write address will have been reset before the same buffer is used next time, so only the necessary frames will always be in the continuous area. is stored in

In the above embodiment, the buffer is divided into two areas, but it is also conceivable to divide it into three or more areas.

〔Effect of the invention〕

As explained above, according to the present invention, even if unnecessary frames are frequently received, the buffer can be saved by simply returning the counter one frame to the previous one without the need for complicated chaining operations. It has the effect of being able to be used by filling it with chopsticks without wasting it.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a reception buffer management device of the present invention. DESCRIPTION OF SYMBOLS 1... Reception control device, 2... Reception buffer management device, 3... Data bus, 4... Sequential circuit, 5, 7...
・Buffer, 6.8...Address generation circuit, 9...
Discrimination control device. 1: “Representative Patent Attorney Susumu Uchihara”

Claims (1)

[Claims] In the reception unit of the communication device, there is a buffer divided into multiple areas for storing received frames, an address generation circuit that specifies write and read addresses for the multiple buffer areas, and a reception control device that indicates frame reception. A sequential circuit inputs a received signal and sequentially stores the received frames in the plurality of buffer areas, and a sequential circuit that determines whether already received frames are necessary or unnecessary, and if the received frames are unnecessary, stores the received frames in the received buffer area in sequence. 1. A reception buffer management device comprising: a determination control device for instructing resetting of said address generation circuit to specify an address of said reception buffer management device.