JPH11191783A - Data transfer method for switching hub and the switching hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the data transfer method for a switching hub having transfer performance capable of dealing with the increase in the number of ports and transmission rate and to provide the switching hub. SOLUTION: In the case that a data transfer control circuit 31 transfers data of a frame received by a communication control LSI 20 for each communication port of the switching hub to each communication port via a common bus 33, the received frame data are compressed and the compressed data are sent to the common bus 33 and the transmitted compression data are decompressed to the original frame data and they are given to the communication control LSI 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub for transferring frame data between a plurality of communication ports, and more particularly to a data transfer method for a switching hub having a transfer performance capable of coping with an increase in the number of ports and the transmission speed. It relates to the switching hub.

[0002]

2. Description of the Related Art As shown in FIG. 4, a switching hub has a plurality of communication ports, and transfers frame data received from a communication port only to a communication port to which a destination terminal of the frame is connected. Communication device. FIG. 4 shows a state in which terminals 41 a to 41 d are connected to the communication ports 1 to 4 of the switching hub 40. When the switching hub 40 receives the frame 42a addressed to the terminal D (41d) from the terminal A (41a) connected to the communication port 1, the switching hub 40 transmits the frame data to the terminal D (41d).
The transfer is performed only to the communication port 4 to which (41d) is connected. At the same time, when receiving the frame 42b addressed to the terminal C (41c) from the terminal B (41b) connected to the communication port 2, the frame data is transmitted to the terminal C (4c).
1c) is transferred only to the communication port 3 to which it is connected.

FIG. 3 shows an internal configuration of a switching hub. The switching hub includes communication control LSIs 30a, 30b, 30c,...
A data transfer control circuit 31a, 31b, 31c,... For controlling frame data transfer between SIs; an address search circuit 32 for searching for a transfer destination port of the received frame data;
A shared bus 33 for transferring frame data;
Buffer memories 34a, 34b, 34c... For temporarily storing the frame data transferred via the H.3, a transfer destination notification bus 35 for notifying the transfer destination information, and a data transfer control circuit 31 to the address search circuit 32. An address search bus 36 is used for transferring a destination address and responding to a transfer destination port from the address search circuit 32 to the data transfer control circuit 31.

FIG. 2 shows the internal configuration of a conventional data transfer control circuit 31. The data transfer control circuit 31 includes a communication control LSI control unit 20, an address detection unit 21, an address search bus control unit 22, a transfer destination notification bus control unit 23, a shared bus control unit 24, and a buffer memory control unit 25. .

Here, the internal operation will be described with reference to FIGS. 2 and 3 by taking as an example a case where a frame addressed to a terminal connected to the communication port 3 is received from the communication port 1 of the switching hub.

In FIG. 3, when a communication control LSI 30a receives a frame, it outputs received frame data to a data transfer control circuit 31a. Data transfer control circuit 31a
Then, the communication control LSI control unit 20
The received frame data from a is output to the address detection unit 21 and the shared bus control unit 24. Shared bus control unit 24
Indicates that the shared bus 3
3 and transfers the received frame data through the shared bus 33. Data transfer control circuits 31b, 31
c, the shared bus control unit 24 transfers the frame data transferred via the shared bus 33 to the buffer memories 34b, 3b.
4c.

On the other hand, in the data transfer control circuit 31a, the address detection unit 21 extracts a destination address (address of the terminal connected to the communication port 3) from the received frame data and notifies the address search bus control unit 22. The address search bus control unit 22 acquires the right to use the address search bus 36, outputs a destination address to the address search circuit 32, and waits for a search result from the address search circuit 32.

[0008] The address search circuit 32 holds a database recording the terminal address and the number of the communication port to which the terminal is connected, and is transferred from the data transfer control circuit 31a using this database. A search is performed to determine which communication port the terminal having the destination address is connected to. When the search is completed, the address search circuit 32 outputs the search result (port number 3) to the address search bus 36.

When receiving the search result from the address search circuit 32, the address search bus control unit 22 of the data transfer control circuit 31a notifies the transfer destination notification bus control unit 23. The transfer destination notification bus control unit 23 includes a transfer destination notification bus 35.
, And outputs transfer destination information (information indicating that it is addressed to the communication port 3).

The transfer destination notification bus control unit 23 of the data transfer control circuit 31b transfers the frame data transferred via the shared bus 33 to the own port from the transfer destination information notified via the transfer destination notification bus 35. And outputs a frame data discard signal to the shared bus control unit 24 and the buffer memory control unit 25. Upon receiving the frame data discard signal, the shared bus control unit 24 stops transferring the frame data to the buffer memory control unit 25, and the buffer memory control unit 25 discards the frame data stored in the buffer memory 34b.

In the data transfer control circuit 31c, the transfer destination notification bus control unit 23 transfers the frame data transferred via the shared bus 33 to the own port from the transfer destination information notified via the transfer destination notification bus 35. Is detected,
No frame data discard signal is output. Therefore, the frame data is stored in the buffer memory 34c. The frame data stored in the buffer memory 34c is read by the buffer memory control unit 25 when the communication control LSI 30c is ready for transmission, and transferred to the communication control LSI 30c via the communication control LSI control unit 20.

As described above, data of a frame received at a certain communication port is transferred only to the communication port to which the terminal of the frame is connected.

[0013]

In the prior art,
When the number of ports increases or the transmission speed of each communication port increases, the transfer performance of the shared bus becomes a bottleneck, and the transfer performance of the switching hub cannot follow such an increase.

An object of the present invention is to solve the above-mentioned problems and to provide a data transfer method in a switching hub having a transfer performance capable of coping with an increase in the number of ports and the transmission speed, and to provide the switching hub.

[0015]

In order to achieve the above object, a data transfer method according to the present invention provides a data transfer control circuit for transmitting data of a frame received by a communication control LSI for each communication port of a switching hub via a common bus. When transferring the data to each communication port, the received frame data is compressed and transmitted to the common bus, and the transmitted compressed data is decompressed into the original frame data and transferred to the communication control LSI. .

Also, the switching hub of the present invention provides a communication control LSI for each communication port for controlling transmission and reception of frames.
And a data transfer control circuit for controlling the transfer of frame data between communication control LSIs via a common bus, the data being transmitted to the common bus by compressing the received frame data from the communication control LSI. And a data expansion unit for expanding the compressed data received from the common bus into original frame data and transmitting the expanded frame data to the communication control LSI.

[0017]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an internal configuration of a data transfer control circuit of a switching hub according to the present invention. This data transfer control circuit is obtained by adding a data compression unit 10 and a data decompression unit 11 to the configuration of FIG. The description of the elements already described is omitted.

The data compression section 10 generates compressed data with a reduced information capacity without losing necessary information from frame data by a predetermined compression algorithm. The data decompression unit 11 restores the compressed data to the original frame data using a decompression algorithm corresponding to the compression algorithm.

As shown in FIG. 1, the data compression unit 10
From the communication control LSI control unit 20 to the shared bus control unit 24
Is inserted into the transmission path. The data decompression unit 1
1 is inserted in the transmission path from the buffer memory control unit 25 to the communication control LSI control unit 20.

Data transfer control circuit 31 of a certain communication port
When the communication control LSI control unit 20 outputs the received frame data to the data compression unit 10, the frame data is compressed by the data compression unit 10 and the compressed data is output to the shared bus control unit 24. Upon detecting the compressed data, the shared bus control unit 24 acquires the right to use the shared bus 33 and transfers the compressed data via the shared bus 33.

Data transfer control circuit 31 of another communication port
In, the compressed data transferred via the shared bus 33 is stored in the buffer memory as it is.

The compressed data read from the buffer memory 34 by the buffer memory control unit 25 is output to the data decompression unit 11. The compressed data is sent to the data decompression unit 1
1 to restore the original frame data. The restored frame data is transferred to the communication control LSI 30 via the communication control LSI control unit 20.

With the above operation, the frame received at the communication port is the same as the frame transmitted from the transfer destination communication port, and the frame data is transmitted to the shared bus 33.
The compressed data is transmitted while the data is stored in the buffer memory 34. Since the compressed data has a small information capacity, more frame data can be transferred than is transferred without changing the frame data.
That is, apparently, the transfer performance of the shared bus 33 is improved. Therefore, even when the number of ports increases or the transmission speed of each communication port increases, the transfer performance of the shared bus is prevented from becoming a bottleneck, and the switching hub responds to the increase in the number of ports and the transmission speed. It will have transfer performance.

[0025]

The present invention exhibits the following excellent effects.

(1) The transfer performance can follow the increase in the number of ports and the transmission speed.

[Brief description of the drawings]

FIG. 1 is an internal configuration diagram of a data transfer control circuit according to an embodiment of the present invention.

FIG. 2 is an internal configuration diagram of a conventional data transfer control circuit.

FIG. 3 is an internal configuration diagram of a switching hub.

FIG. 4 is a configuration diagram of a network using a switching hub.

[Explanation of symbols]

 Reference Signs List 10 Data compression unit 11 Data decompression unit 20 Communication control LSI control unit 24 Shared bus control unit 25 Buffer memory control unit 30 Communication control LSI 33 Shared bus 34 Buffer memory

Claims (2)

[Claims] When a data transfer control circuit transfers data of a frame received by a communication control LSI for each communication port of a switching hub to each communication port via a common bus, the received frame data is compressed and compressed. A data transfer method in a switching hub, wherein the data is transmitted to a common bus, and the transmitted compressed data is decompressed into original frame data and passed to the communication control LSI. 2. A communication control LSI for each communication port for controlling transmission and reception of frames, and each communication control LSI via a common bus.
A switching hub having a data transfer control circuit for controlling frame data transfer between SIs, a data compression unit for compressing received frame data from the communication control LSI and sending the compressed data to the common bus; A switching hub, comprising: a data decompression unit for decompressing compressed data into original frame data and transmitting the decompressed data to the communication control LSI.