JPH09186707A - Information transfer controller and input output control port used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information transmission controller in which the number of pins for a frame controller is reduced without losing a back pressure function and the input output control port used for the controller. SOLUTION: A BPREQ(back pressure request signal) transmission pin is provided to a frame controller 1, and an input output control port 3 is provided with a 1st register 7 storing number of received frames per unit time and a 2nd register 8 storing a threshold level relating to the received frame number per unit time and the input output control port causes automonously a back pressure only when the content of the 1st register is larger than the content of the 2nd register at the time of the reception of the BPREQ.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information transfer control device and an input / output control port used for the same.
The present invention relates to an information transfer control device suitable for use in a digital information communication network such as a LAN (local area network) and an input / output control port used for the same.

[0002]

2. Description of the Related Art In digital information communication networks such as LAN, various communication systems have been constructed to support smooth communication between users. Among them, C
The SMA / CD (carrier sense multiple access / collision detection) system and the like are widely used.

In order to embody such a system, Ethernet, which is a typical network communication device, has been conventionally used.
For (Ethernet), an information transfer control device (Ethernet switch) as shown in the block diagram of the main part of FIG. 2 is used. In FIG. 2, 2 is a frame memory, 4 is an internal bus line, 5 is a read / write signal (R / W) line,
9 is an external communication line connected to the user's terminal, 10 is a conventional frame controller, 30 is a conventional input / output control port (Ethernet controller), 60 is a back pressure request signal (BPREQ) line, and 70 is a received frame counter. . A frame is a destination (DA
(Referred to as “destination address”) means one piece of information that is transferred.

As shown in FIG. 2, the information transfer control device comprises a plurality (n in FIG. 2) of input / output control ports 30 such as Ethernet controllers. When the frame is transferred to the input / output control port 30 through the external communication line 9, the frame controller 10 recognizes the DA and sends the frame to the DA via the internal bus line 4.
The data is transferred to the input / output control port 30 (abbreviated as DA port) corresponding to. The transfer method is cut-through (cut t) that transfers the received frame from the outside directly to the DA port.
hrough method and store and forward (store and for war)
d) There are methods.

In the cut-through method, even if a new frame arrives when the DA port is busy (busy = busy), it is discarded, but in the store-and-forward method, Since this can be temporarily stored in the frame memory 2, frames transferred one after another are not discarded until the frame memory 2 becomes full.

During operation of the store-and-forward method, the frame controller 10 sends a signal to a read / write signal (abbreviated as R / W) line 5 to control the frame memory 2 while controlling a certain source port. Is busy and the frame memory 2 is about to overflow, and the back pressure (bac
k pressure) Send a request signal (abbreviated as BPREQ as appropriate). And the input / output control port 30 that received BPREQ
Each stops accepting the frame transferred to itself (also referred to as "back pressure" because it operates to "push back" the frame). In order to provide such a back pressure function, a BPREQ line 60 is wired between the frame controller 10 and the input / output control port 30 in a one-to-one correspondence.

Each input / output control port 30 is normally provided with a reception frame counter (recei
ved frame cuonter) 70 is provided.

[0008]

As described above, in the conventional information transfer control device, the BPREQ line 60 has a one-to-one correspondence between the frame controller and the input / output control port 30.
Are wired. On the other hand, this type of information transfer control device is not integrated in one chip in order to support various communication systems that are frequently improved.
10, the frame memory 2, the input / output control port 30 and the like are independently manufactured as one chip, and these are mounted on a board or the like and arranged and wired. Therefore, the chip manufactured as the frame controller 10 requires as many pins as the input / output control ports 30. Therefore, the number of pins of the frame controller 10 increases as the number of users increases, and the chip becomes large.

Therefore, it is an object of the present invention to provide an information transfer control device which can reduce the number of pins of a frame controller without impairing the back pressure function and an input / output control port used therefor.

[0010]

SUMMARY OF THE INVENTION The present invention is connected to each of a plurality of external communication lines and an internal bus line to transmit / receive a frame and suppress the frequency of transmission to another device in response to a first signal. It has an input / output control port that has a function to enable it, a frame memory that is connected to the internal bus line and temporarily stores received frames, controls the read / write operation of the frame memory, and detects that the frame memory is almost full. And an information transfer control device including a frame controller that sends a first signal to the input / output control port,
The frame controller sends the first signal to all the input / output control ports all at once, and each input / output control port autonomously sends the other signals to other devices when receiving the first signal in light of its own frame reception status. It is characterized by requesting that the transmission frequency be suppressed.

Further, the present invention is an input device having a function of connecting to each of a plurality of external communication lines and an internal bus line to transmit / receive a frame and suppressing a transmission frequency to another device in response to a first signal. Output control port, frame memory connected to internal bus line for temporarily storing received frames, read / write operation of frame memory, and detecting just before frame memory is full A first register for storing the number of received frames per unit time, which is the input / output control port mounted on an information transfer control device including a frame controller that sends a first signal to a control port all at once; A second register for storing a threshold value relating to the number of received frames per unit time, and the value of the first register is set to the second register when receiving the first signal. An input-output control port, characterized by asked to suppress the transmission frequency with respect to viewing another device when larger than the value.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of essential parts showing an information transfer control device of the present invention. In FIG. 1, 1 is a frame controller according to the present invention, 3 is an input / output control port according to the present invention, 6 is a first signal (BPREQ) line, and 7
Is a first register that stores the number of received frames per unit time, and 8 is a second register that stores a threshold value related to the number of received frames per unit time. The same members as those shown in FIG. 2 are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 1, the information transfer control device of the present invention is connected to each of a plurality of external communication lines 9 and an internal bus line 4 to transmit / receive a frame and to transmit it through a first signal line 6. An input / output control port 3 for stopping reception of received frames in response to a first signal corresponding to a back pressure request signal (BPREQ), and a frame memory 2 connected to an internal bus line 4 for temporarily storing received frames. A frame controller 1 for controlling the read / write operation of the frame memory 2 and for inputting and outputting the first signal to the input / output control port 3 upon detecting that the frame memory 2 is almost full. In the information transfer control device, the frame controller 1 is
The REQ is transmitted to all the input / output control ports 3 at the same time, and each input / output control port 3 autonomously stops or continues the reception when receiving the BPREQ according to its own frame reception status. .

Since the present invention is configured in this way, the frame controller 1 only needs to have one BPREQ transmission pin. Further, since each input / output control port 3 decides by itself whether to accept the reception of the frame transferred to itself, the back pressure function relating to the information transfer control is not impaired. The input / output control port 3 of the present invention, which can be suitably used in the information transfer control device of the present invention, includes, in addition to the conventional received frame register 70, a first register 7 for storing the number of received frames per unit time and a unit. A second register 8 for storing a threshold value relating to the number of received frames per time, and only when the value of the first register 7 is larger than the value of the second register 8 when receiving BPREQ. It is characterized by stopping.

That is, the input / output control port 3 of the present invention always stores the instantaneous value of the number of frames it is flowing, its threshold value, and the magnitude relationship between these instantaneous values / threshold values. When the BPREQ broadcast is received, only the input / output control port 3 whose instantaneous value is larger than the threshold value, that is, which has a high contribution rate to the overflow of the frame memory 2, immediately stops accepting the received frame. That is, the input / output control port 3 of the present invention can determine whether to accept the reception of the frame transferred to itself.

The time width (unit time) for fetching the number of received frames in the first register 7 and the setting of the value (threshold value) in the second register are set according to the operation record of each input / output control port 3 of the information transfer control device. It is rational to review based on the above and review every appropriate period. As is clear from the above description,
INDUSTRIAL APPLICABILITY The information transfer control device of the present invention and the input / output control port used therefor are suitably used for a switching hub (meaning frame transfer means) of various network communication devices with a back pressure function represented by an Ethernet switch. it can.

[0017]

According to the present invention, the number of pins of a frame controller mounted on an Ethernet switch or a switching hub having a similar function can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of essential parts showing an information transfer control device of the present invention.

FIG. 2 is a principal block diagram showing a conventional information transfer control device.

[Explanation of symbols]

1 Frame Controller According to the Present Invention 2 Frame Memory 3 Input / Output Control Port of the Present Invention 4 Internal Bus Line 5 Read / Write Signal (R / W) Line 6 First Signal Line 7 First Register 8 Second Register 9 External communication line 10 Conventional frame controller 30 Conventional input / output control port (Ethernet controller) 60 Back pressure request signal (BPREQ) line 70 Received frame counter

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Yoshizawa 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Works (72) Inventor Yoshihiro Ishida 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Saki Steel Co., Ltd.

Claims (2)

[Claims] 1. An input / output control port, which is connected to each of a plurality of external communication lines and an internal bus line, has a function of transmitting and receiving a frame, and having a function of suppressing a transmission frequency to another device according to a first signal. A frame memory connected to the internal bus line for temporarily storing a received frame; and a read / write operation of the frame memory, and detecting that the frame memory is about to be full, the first input / output control port is detected. In the information transfer control device provided with the frame controller for sending the signal, the frame controller simultaneously transmits the first signal to all the input / output control ports, and each input / output control port receives the first signal, An information transfer control device characterized by autonomously requesting another device to suppress the transmission frequency in light of its own frame reception status. 2. An input / output control port, which is connected to each of a plurality of external communication lines and an internal bus line, has a function of transmitting and receiving a frame, and having a function of suppressing a transmission frequency to another device in response to a first signal. And a frame memory that is connected to the internal bus line to temporarily store the received frame, controls the read / write operation of the frame memory, and detects that the frame memory is about to be full, A first register for storing the number of received frames per unit time, the input / output control port being mounted on an information transfer control device equipped with a frame controller for sending a first signal all together, And a second register for storing a threshold value regarding the number of received frames, and the value of the first register is larger than the value of the second register when the first signal is received. An input / output control port that requests another device to suppress the transmission frequency only when it reaches a threshold.