JP2001036559A - Device and method for automatically adjusting data transfer rate for preventing generation of overflow in ethernet (registered trademark) switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of overflow by automatically setting transfer rate of an external device so as to be matched to the transfer rate which is assisted by a switch, interfacing data to be transferred and adjusting the inputted data transfer rate by reducing it by outputting a controlling signal when the overflow of the inputted data occurs in a switch. SOLUTION: A line connecting part 202 is provided by every port as a physical hierarchical part to connect an external terminal such as a PC 100 with an Ethernet switch 102. And communication is performed with a terminal, etc., to be connected by every port, the data transfer rate is automatically set and recorded in an internal register. When data runaway is generated on a transmission line because the data transfer rate to be inputted in a buffer 206 is faster than the data transfer rate to be outputted, the line connecting part 202 is controlled so that the data transfer rate to be transmitted from the external terminal to the line connecting part 202 becomes lower by a line rate control part 204.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an Ethernet switch (Ethernet (registered trademark) Switch).
The present invention relates to an apparatus and method for automatically adjusting a data transmission rate for preventing and eliminating overflow in an Ethernet switch supporting various transmission rates.

[0002]

2. Description of the Related Art FIG. 1 schematically shows a system configuration of a general Ethernet network. Ethernet switches 102 and 104 are IEEE802.3.
u of 100Base-T and IEEE802.3ab 1
000Base-T, and the Ethernet switches 102 and 104 can support a line in which the same port has various transmission speeds. Therefore, 10 Mbps, 100 Mbps in one switch device
There may be ports with speeds of up to 1 Gbps or 1 Gbps. Here, usually, the Ethernet switch 102
A terminal such as the PC 100 is connected to the low transmission rate line, and a server (not shown) or another Ethernet switch 104 is connected to the relatively high transmission rate line. Become like

At this time, communication between ports having the same speed, that is, for example, 10 Mbps port and 10 Mbps
The communication between the s port, the 100 Mbps port and the 100 Mbps port is a data runaway except in a special case unless many input ports send data to one output port such as port aggregation. (C
ongestion) does not occur.

However, a 100 Mbps port is 10M
10 bps ports or 1000 Mbps ports
When attempting to transmit data to the 0 Mbps port, there is a problem that data is forced to be stuck in the switch due to the occurrence of overflow due to the occurrence of data runaway.

[0005] That is, for example, the port speed of the connection line between the external terminal PC 100 and the Ethernet switch 102 is 100 Mbps, and the Ethernet switch 1
PC1 if the transmission speed between 02 and 104 is 10 Mbps
When data is continuously transmitted at 100 Mbps from the 00 side, this transmission data is forced to be accumulated in the Ethernet switch 102. At this time, if this Ethernet switch is a switch using a shared buffer (Shared buffer), it is also transmitted to other ports. As a result, there is a problem that the throughput (throughput) of the entire network is rapidly reduced.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an apparatus and method for automatically adjusting a data transmission rate for preventing and eliminating overflow in an Ethernet switch.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an Ethernet switch having a transmission speed automatic adjustment function and a port for supporting various transmission speeds. Automatically setting a transmission rate of an external device connected to a port to be connected to a transmission speed supported by the switch, interfacing data transmitted between the external device and the switch, and When an overflow occurs in the switch due to data input from the switch, a control signal for reducing the transmission speed of the input data so as to match the output transmission speed of the data is output to the line connection unit and the input data transmission is performed. It is characterized in that the speed is adjusted down.

[0008]

Preferred embodiments according to the present invention will be described below in detail with reference to the accompanying drawings. Many specific details, such as specific process flows, are set forth in the following description and accompanying drawings to aid in a more general understanding of the present invention. It will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details.

FIG. 2 shows a block diagram of an automatic data transmission speed adjusting device inside the Ethernet switch according to the embodiment of the present invention. Referring to FIG. 2, the line connection (Auto Negotiable PHY) 202 is a P
External terminal such as C100 and Ethernet switch 1
02 is provided for each port as a physical layer unit for connecting to a port 02, and communicates with a terminal or the like connected to each port to automatically set a data transmission rate and record it in an internal register. That is, since each port of the Ethernet switch 102 is designed to support 10 Mbps / 100 Mbps, the transmission rate must be automatically adjusted to match the data transmission rate of the terminal connected to each port. The connection unit 202 automatically and appropriately sets the data transmission speed so as to match the transmission speed with the external terminal using an automatic transmission speed setting function (Auto Negotiation). Line speed control unit (Buffer Monitoring
The controller 204 receives packet data transmitted from the terminal through each port, performs predetermined data processing, temporarily stores the data in a buffer 206, and stores packet data read from the buffer 206 to the port. Transmit. In addition, the transmission rate of data input / output from the buffer 206 is checked. If the data transmission rate input to the buffer 206 is higher than the output data transmission rate, and data runaway occurs on the transmission path, the line connection unit 2
02 is controlled so that the data transmission rate transmitted from the external terminal to the line connection unit 202 is reduced.

FIG. 3 is a flowchart showing a process for automatically down-adjusting the data transmission speed of a line when a data runaway occurs according to an embodiment of the present invention. Hereinafter, FIG.
An embodiment of the present invention will be described in detail with reference to FIG. In the description of the embodiment of the present invention, the data transmission rate input from the external terminal PC connected to the input port "A" of the Ethernet switch is 100 for convenience of explanation.
Mbps, and the data transmission rate of the output port “B” of the switch is assumed to be 10 Mbps.

First, when an external terminal such as the PC 100 is connected to the Ethernet switch 102 through the input port “A”, the line speed control unit 204 controls the physical layer control register (Control layer) provided in the line connection unit 202.
The transmission bit automatic setting function activation bit of the PHY register is set to logic “high”, that is, a logical value “1”, and the external terminal PC 100 is connected to the external terminal PC 100 through the transmission rate automatic setting function of the line connection unit 202 at step 300 An optimum data transmission rate for data transmission / reception is set between the switch 102 and the switch 102. That is, the line connection unit 202 has the port “A” of 10 Mbps as in the embodiment of the present invention.
/ 100Mbps shared port and external terminal PC10
When 0 is also used for 10 Mbps / 100 Mbps, the data transmission speed is normally determined to be 100 Mbps in the line connection unit 202 by the automatic transmission speed setting function. As a result, data is transmitted from the external terminal PC 100 to the switch 102 at the determined transmission speed through the port “A”. Then, the line speed controller 204 proceeds to step 302 to check whether data transmitted from the external terminal PC 100 through the port “A” is received. Then, the received data is temporarily stored in the buffer 206. Next, the line speed controller 204 proceeds to step 306 to sequentially read the data stored in the buffer 206 and transmit the data to the destination node through the port “B”. Then, the line speed control unit 204 proceeds to step 308 to check whether an overflow due to data runaway occurs. As described above, this overflow is one of the unfavorable situations in which, in the case of a switch using a shared buffer, it also affects other ports and rapidly reduces the data processing amount of the entire network. When the transmission speed is higher than the transmission speed of the output data, the data is input to the PC 100 immediately and is not output to the destination node but is accumulated in the buffer 206 in the switch 102. Part 2
No. 04 monitors the data flow on the transmission path, grasps the input data transmission speed and the output data transmission speed, and determines whether or not overflow is possible.

At this time, if the overflow does not occur, the line speed control unit 204 returns to the step 302 and performs the steps 302 to 308 again. If the overflow occurs separately, the step proceeds to the step 310. A transmission speed reduction control signal for reducing the transmission speed of the input data from the external terminal PC 100 is generated and applied to the line connection unit 202. That is, the control signal sets the transmission rate bit of the physical layer control register in the line connection unit 202 to logic “Low”, that is, the logic value “0”, and the transmission rate automatic setting function activation bit The logical speed is set to “0” and the transmission speed is reduced to 10 Mbps. As a result, at the stage 312, the line connection portion 20
2, the external terminal PC using the transmission speed reduction control signal
100 transmission speed is reduced and the external terminal PC
The transmission speed set between the switch 100 and the switch 102 is adjusted down so that the transmission speed of the output port "B" matches the transmission speed.

[0013]

As described above, according to the present invention, in the Ethernet switch supporting various transmission speeds, the transmission speed of the input port and the data transmission speed of the output port are automatically adjusted so as to match each other. Overflow on the transmission line is prevented and data loss is prevented.
Also, it is possible to prevent a reduction in the data processing amount of the entire network.

[Brief description of the drawings]

FIG. 1 is a schematic system configuration diagram of a conventional Ethernet network.

FIG. 2 is a block diagram of an automatic data transmission rate adjusting device according to an embodiment of the present invention.

FIG. 3 is an operation control flowchart for adjusting a data transmission rate according to an embodiment of the present invention;

[Explanation of symbols]

 102 Ethernet switch 200, 202 Line connection unit 204 Line speed control unit 206 Buffer

Claims (2)

[Claims] 1. An automatic transmission rate adjusting apparatus for preventing an overflow from occurring in an Ethernet switch having ports supporting various transmission speeds, wherein the transmission speed of an external device connected to the port supporting the transmission speed is controlled. A line connection unit configured to automatically set a transmission speed supported by the switch and to interface data transmitted between the external device and the switch; and A line speed control unit that outputs a control signal for reducing the transmission speed of the input data to the line connection unit so as to match the output transmission speed of the data when the overflow occurs, thereby adjusting the input data transmission speed down. Under the control of the speed control unit, data transmitted through the line connection unit An automatic transmission speed adjusting device for preventing an overflow from occurring in an Ethernet switch, comprising a buffer for temporarily storing data. 2. A method for preventing an overflow from occurring in an automatic transmission rate adjusting apparatus in an Ethernet switch having a port supporting various transmission speeds, the transmission speed of an external device connected to the port supporting the transmission speed. Automatically setting to match the transmission rate supported by the switch, and temporarily storing data input from the external device in the buffer at the set transmission rate, and then transmitting the data to the destination node, When an overflow of data input from the external device occurs, a control signal for reducing the transmission speed of the input data to the line connection unit so as to match the output transmission speed of the data is output to reduce the input data transmission speed. Down-adjustment process.