JPH06252933A - Interface device for loop type local area network - Google Patents

Abstract

PURPOSE:To provide an interface device for loop type local area network which can minimize the delay caused when the data that just pass through each interface device connected to a transmission line are relayed. CONSTITUTION:A frame buffer part 105 is provided together with a selector 203, a data cross connecting part 106, and a data terminal corresponding part 107. The part 105 transmits the received data, if not addressed to the part 105 itself, to a transmission line through the selector 203 based on only the difference (optical between the phase of the transmitted data and the phase of the received data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving data transmission in a local area network, and more particularly to improving an interface device of a loop type local area network.

[0002]

2. Description of the Related Art In recent data transmission technology, high speed data transmission is an indispensable technology. For this reason,
In a system such as a local area network (hereinafter referred to as LAN) in which data is relayed through a single transmission path through many devices, it is important to minimize the data transfer delay within each device. It is a problem.

FIG. 4 is a schematic diagram showing a system configuration of a conventional loop LAN. In FIG. 4, reference numeral 100 is a transmission line, and in this example, four interface devices 101,
A loop network is formed by connecting 102, 103, and 104 in order. Each interface device 10
1, 102, 103 and 104 have the same configuration, and FIG. 4 shows only the configuration of the interface device 101.

The conventional interface device 101 is mainly composed of a data cross connect unit 106 and a data terminal corresponding unit.
It is composed of 107 and, in addition, CPU etc. for controlling them are also provided. Although not shown in FIG. 4,
Various terminal devices are further connected to the data terminal corresponding unit 107.

The data cross connect unit 106 is a transmission line 100.
The data is switched between the data terminal corresponding unit 107 and the data terminal corresponding unit 107, and when the data is not switched between the data terminal corresponding unit 107 and the data terminal corresponding unit 107, a relay process for transmitting the received data as it is to the transmission path 100 is performed. To do. The data terminal corresponding unit 107 receives data from the data cross connect unit 106 and outputs it to various terminal devices not shown, and conversely outputs data input from various terminal devices to the data cross connect unit 106.

For example, when data (transmission path reception data) is transmitted from the interface device 104 to the interface device 101 via the transmission path 100, the data should be addressed to an interface device other than the interface device 101. For example, the data cross connect unit 106 of the interface device 101 outputs the received data as it is as the transmitted data. This transmission data is transmitted from the interface device 101 to the transmission line 100 as transmission line transmission data and is received by the interface device 102.

On the other hand, if the transmission path reception data received by the interface apparatus 101 from the interface apparatus 104 via the transmission path 100 is data destined for the interface apparatus 101, the data cross-connect unit 106 fetches the received data. Then, it is output to the data terminal corresponding unit 107 as terminal reception data. Further, when there is data to be transmitted from the data terminal corresponding unit 107 to another interface device 102, 103 or 104, the data is sent from the data terminal corresponding unit 107 to the data cross connect unit 106 as terminal transmission data. In the data cross-connect unit 106, if there is a vacant transmission frame on the transmission path 100, the data is placed on the vacant frame and transmitted as transmission path transmission data.

Note that the data cross-connect unit 106 has a two-sided memory configuration, and in the case of data that is simply relayed, in other words, from the input to the data cross-connect unit 106 until it is output, in other words, Interface device 10
There is a 1 to 2 frame delay between the reception of the data at 1 and the transmission of the data.

[0009]

As described above, the conventional L
In the AN system, each interface device causes a delay of 1 or 2 frames when simply relaying data addressed to another interface device. By the way, each interface device generally has a low ratio of data addressed to itself to all data transmitted to itself. This ratio decreases as the number of interface devices connected to the same transmission line increases.
Therefore, the more interface devices, the more LAN
The data transmission rate will be reduced in the entire system.

The present invention has been made in view of the above circumstances, and it is possible to minimize the delay in relaying data that simply passes through each interface device connected to a transmission path. An object is to provide an interface device for a loop type local area network.

[0011]

FIG. 1 is a schematic diagram showing a system configuration of a loop LAN for explaining the principle of an interface device of a loop type local area network according to the present invention.

In FIG. 1, reference numeral 100 is a loop-shaped transmission line, and in this example, four interface devices 10 are provided.
1, 102, 103, 104 are connected to form a loop network. Interface device 101, 102, 103, 1
04 have the same configuration, and FIG. 1 shows only the configuration of the interface device 101.

The interface device 101 is mainly composed of a frame buffer unit 105, a selector 203, a data cross connect unit 106, and a data terminal corresponding unit 107. In addition, a CPU for controlling these is also provided. It is equipped. Although not shown in FIG. 1, various terminal devices are further connected to the data terminal corresponding unit 107.

The frame buffer section 105 is composed of an elastic memory for storing and outputting the transmission path reception data received from the transmission path 100 in units of one frame. The elastic memory is a memory that can simultaneously perform a data writing operation and a data reading operation. Therefore, the frame buffer unit 105 can output the transmission path reception data to the data cross connect unit 106 and the selector 203 only with the phase difference (arbitrary) between the phase of the transmission data and the phase of the reception data.

The data cross-connect unit 106 is composed of a two-sided memory. The data cross-connector 106 alternately stores the received data output from the frame buffer unit 105 in the two-sided memory. Are alternately output to the data terminal corresponding unit 107 from the two memories as the terminal reception data. If there is data to be transmitted from the data terminal corresponding unit 107, it is alternately stored in the two-sided memory as terminal transmission data, and if there is an empty frame on the transmission path 100, the two-sided memory is stored. Are alternately output as transmission data.

The data terminal correspondence unit 107 receives the terminal reception data from the data cross connect unit 106 and outputs it to various terminal devices not shown, and conversely, the terminal transmission data input from various terminal devices is data crossed. Output to the connecting unit 106.

The input of the selector 203 is a frame buffer section
105 and the data cross connect unit 106, and the output is connected to the transmission line 100. If the transmission path reception data received by the interface device 101 is not addressed to itself, the selector 203 determines that the frame buffer
By selecting 105, the data cross connect unit 106
Data that does not pass through is transmitted to the transmission path 100 as relay data. If there is terminal transmission data from the data terminal corresponding unit 107 of the interface device 101 itself, the selector 20
3 selects the data cross-connect unit 106 and transmits the transmission data to the transmission line 100 as transmission line transmission data.

[0018]

Now, for example, when the transmission path reception data is received from the interface device 104 to the interface device 101 via the transmission path 100, the transmission path reception data should be addressed to an interface device other than the interface device 101. For example, since the selector 203 of the interface device 101 selects the frame buffer unit 105, the transmission path reception data is sent from the frame buffer unit 105 to the interface device 10 as it is.
It is transmitted to the transmission line 100 as a transmission line transmission toward 2.
In this case, the frame buffer unit 105 causes only a delay due to the phase difference between the receiving side data and the transmitting side data.

On the other hand, if the transmission path reception data received from the interface device 104 to the interface device 101 via the transmission path 100 is the data addressed to the interface device 101, the selector 203 causes the frame buffer unit 10 to operate as described above.
When 5 is selected, the received data is sent as is to the transmission path 100 as transmission path transmission data, but the data cross-connect section 106 also receives the reception data from the frame buffer section 105 and sends it as terminal reception data to the data terminal corresponding section 107. .

When there is data to be transmitted from the data terminal corresponding unit 107, that is, terminal transmission data, the selector 203 selects the data cross connect unit 106. As a result, the terminal transmission data is sent from the data terminal corresponding unit 107 to the data cross connect unit 106, and if there is a free transmission frame on the transmission path 100, the data cross connection unit 106 transmits it to the empty frame via the selector 203. It is transmitted as road transmission data.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments thereof. FIG. 2 is a block diagram showing the configuration of an embodiment of an interface device for a loop type local area network according to the present invention.

The interface device 101 is mainly composed of a frame buffer unit 105, a selector 203, a data cross connect unit 106, a data terminal corresponding unit 107, and a CPU 108 for controlling them. Although not shown in FIG. 2, various terminal devices are further connected to the data terminal corresponding unit 107.

The frame buffer unit 105 is a frame memory
It has a 201 and a control memory 202. The frame memory 201 is composed of an elastic memory that stores the transmission path reception data received from the transmission path 100 in 1-frame units and outputs the same. The phase difference between the phase on the transmission side and the phase on the reception side (arbitrary) ) Only, outputs the transmission path reception data to the data cross connect unit 106 and the selector 203.

Control information is given to the control memory 202 from the CPU 108. This control information is
This is information indicating whether or not each frame of the transmission path reception data received from 0 is relay data, and is mapped to the control memory 202. Control memory 202
The control information mapped to is sequentially given to the selector 203 to control the selection operation of the selector 203.

The data cross-connect unit 106 includes a first frame memory 205 and a second frame memory 208 each having two faces for transmission and reception, and a selector for selectively controlling reading of data from each face of the first frame memory 205. 206 and the second
A selector 209 for selectively controlling reading of data from each side of the frame memory 208, a first control memory 204, a second control memory 207 for controlling both frame memories 205, 208 and both selectors 206, 209 are provided. ing.

The first frame memory 205 alternately stores the received data output from the frame memory 201 of the frame buffer unit 105 or the terminal transmission data output from the data terminal corresponding unit 107 in the two-sided memory, and at the same time, selects the selector. Output to 206. The data output from this selector 206 is given to the selector 203 as transmission data. The second frame memory 208 alternately stores the received data output from the frame memory 201 of the frame buffer unit 105 or the terminal transmission data output from the data terminal corresponding unit 107 in the two-sided memory and the selector 206. Output to. The data output from the selector 209 is given to the data terminal corresponding unit 107 as terminal reception data.

Control information similar to that of the control memory 202 of the frame buffer unit 105 is given to the control memories 204 and 207 from the CPU 108 and is mapped to the control memories 204 and 207. The control information mapped to both the control memories 204 and 207 is sequentially given to both the frame memories 205 and 208 and both the selectors 206 and 209, and which side of the both frame memories 205 and 208 is to be written with data or which side. Controls whether to read data from and the selection operation of both selectors 206 and 209.

The data terminal corresponding unit 107 receives the terminal reception data from the selector 209 and outputs it to various terminal devices not shown, and conversely, the terminal transmission data input from the various terminal devices is stored in both frame memories 205, 205. Output to 208.

The operation of the interface device of the loop type local area network of the present invention having such a configuration will be described with reference to the timing chart of FIG.

Now, for example, as shown in FIG.
When the transmission path reception data as shown in (b) is received, the data is first transmitted in frame units in the frame memory.
As shown in FIG. 3 (a) in 201, the data is written in synchronization with the phase of the transmitting side data, and at the same time as shown in FIG. 3 (c), is read in synchronization with the phase of the receiving side data. The phase difference is absorbed and the selector 203 and both frame memories
Written in 205, 208.

If, for example, the transmission path reception data is data addressed to another interface device, that is, relay data, control information indicating that the frame is relay data is stored in the control memory 202 from the CPU 108. There is. Therefore, since the selector 203 selects the frame memory 201 side, it is read from the frame / frame memory 201 as relay data and immediately transmitted to the transmission line 100 as transmission line transmission data.

On the other hand, for example, if the transmission path reception data is the data addressed to the interface device 101, the selector 203 selects the frame memory 201 and the transmission path reception data is directly transmitted to the transmission path 100 as the transmission path transmission data as described above. The data is transmitted, but at the same time, in the data cross-connect unit 106, it is stored in the second frame memory 208 as received data as shown in FIG. 3 (d) under the control of the second control memory 207. The data stored in the second frame memory 208 is the selector as shown in FIG. 3 (e).
It is read by 209 and sent to the data terminal corresponding unit 107 as terminal reception data.

When there is data to be transmitted from the data terminal corresponding unit 107, that is, terminal transmission data, the terminal transmission data is stored in the first frame memory 205 under the control of the first control memory 204. The selector 206 reads the data stored in the frame memory 205 and outputs it to the selector 203 as transmission data. selector
203 is a selector under the control of the control memory 202
The data read by 206 is selected and output to the transmission path 100 as transmission path transmission data.

[0034]

As described in detail above, according to the present invention,
Since the data that is only relayed through each interface device can be transmitted to the transmission path with the shortest delay after being received from the transmission path, the data transmission speed can be increased.

[Brief description of drawings]

FIG. 1 is a loop type for explaining the principle of an interface device of a loop type local area network according to the present invention.
It is a schematic diagram which shows the system configuration of LAN.

FIG. 2 is a block diagram showing a configuration of an embodiment of an interface device of a loop type local area network according to the present invention.

FIG. 3 is a timing chart for explaining the operation of the interface device of the loop type local area network of the present invention.

FIG. 4 is a schematic diagram showing a system configuration of a conventional loop LAN.

[Explanation of symbols] 101 Interface device 105 Frame buffer unit 106 Data cross-connect unit 107 Data terminal corresponding unit 203 Selector

Claims (1)

[Claims] 1. A data terminal corresponding unit (107), each of which is connected in a loop by a transmission line (100) and realizes an interface with a terminal device, and the transmission line (10).
0) from the transmission path data and the data terminal corresponding unit (107)
Loop type local area network provided with a data cross-connect unit (106) for switching between terminal data from the device or transmission line data to the transmission line (100) and terminal data to the data terminal corresponding unit (107). In the interface device, the frame buffer section (105) for temporarily storing the data received from the transmission path (100), and the output data from the frame buffer section (105) or the data cross-connect section (106). A selector (203) for selecting any one of the output data from and transmitting it to the transmission path (100), and the transmission path data received from the transmission path (100) is data addressed to another interface device. Is output data from the frame buffer unit (105), and if there is terminal data to be transmitted from the data terminal corresponding unit (107), the data cross connect unit (106) Interface device of the loop the local area network, characterized in that the output data of al and control means (202) for selectively each of said selector (203).