JPH04320130A - Data communication system - Google Patents

Abstract

PURPOSE:To effectively utilize a transmission line and to transfer lots of data at a high speed. CONSTITUTION:The communication control between plural nodes 2 connected to a transmission line 1 in a loop is implemented by a communication monitor controller 7. The communication monitor controller 7 forms a frame sent to the transmission line 1 with a frame header and a control time slot when no data transfer request is received and forms the frame with a frame header, a control time slot and a time slot allocated only to a node having the data transfer request when a data transfer request is received.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication system, and more particularly to a frame structure for a data access system in a loop network communication system.

0002

2. Description of the Related Art Conventionally, loop type network communication systems have been used as local area networks. FIG. 5 is a configuration diagram of a conventional TDM type loop type network communication system described in, for example, Japanese Patent Application Laid-Open No. 61-265938. Nodes numbered 1 to n of which the network is configured, 7 is a communication control and monitoring device. In a loop-type network communication system,
The communication control device 7 is a system in which a frame signal is sent to the loop-shaped data transmission line 1, and each node 2 communicates with each other according to this frame signal.

FIG. 6 is a frame configuration diagram of the TDM system. In the same figure, FH is a frame header, TS1, T
S2, TS3, ...TSn are time-divided channels (transmission paths: time slots) fixedly allocated to node 1, node 2, node 3, ... node n, respectively.

Next, the operation of the above-mentioned conventional system will be explained. The communication monitoring control device 7 connects the loop type transmission line 1 to the
A frame signal shown in FIG. 1 is constantly sent out, and a channel is dedicated at a ratio of 1:1 between communicating nodes to perform data communication. For example, when communicating between node L and node M, node L receives data during time slot TSI. On the other hand, node MM transmits data in time slot THm and transmits data in time slot TSl.
Receive data when . In this way, each node in the network can communicate data with each other.

[0005]

[Problem to be Solved by the Invention] Since the conventional TDM loop network communication system is configured as described above, a fixed time slot is assigned even to a node that does not have a data transfer request. The transmission path is not fully utilized because the slot is sent to the transmission path while it is empty. Furthermore, in order to transfer a large amount of data, the time slots fixedly assigned to each node must be repeatedly used many times, resulting in the problem that high-speed transfer cannot be performed. The present invention was made to solve the above-mentioned problems, and its purpose is to provide a data communication method that makes effective use of transmission paths and can transfer large amounts of data at high speed. .

[0006]

[Means for Solving the Problems] The present invention connects a plurality of nodes to which terminals are connected in a loop through a transmission path, and communicates data between each node in a plurality of time-divided time slots using a communication control device. In a data communication system that performs
When there is no data transfer request, it consists of a frame header and a control time slot, and when there is a data transfer request, it consists of a frame header, a control time slot, and a time slot allocated only to the node with the data transfer request. I did it like that.

[0007]

According to the present invention, the communication control device constructs a frame with a frame header, a control time slot, and a time slot assigned only to a node requesting data transfer, and sends the frame to a transmission path.

[0008]

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings. FIG. 1 is a configuration diagram of a TDM type loop network communication system according to the present invention, in which 1 is a data transmission path, 2 is a data transmission path 1, and nodes numbered 1 to n constitute a loop network; 3 is a terminal connected to node 2, and 4 and 5 are time-divided channels (time slots) used for data transfer between nodes.
, 6 is a common control channel for controlling data transfer, and 7 is a common control channel 6 that is used to control channels such as channel allocation and release in response to transfer requests and termination requests from node 2. It is a communication monitoring and control device.

FIG. 2 is a diagram showing the structure of a frame sent to a transmission path, and shows an embodiment of the present invention. In the figure, 11 is a frame header indicating the attributes of frame contents and transferred data, 12 is a control time slot, and 13 to 1
Reference numeral 6 denotes time slots assigned to nodes 1, n, 2, and l, respectively, in response to transfer requests.

FIG. 3 is a block diagram of the communication monitoring and control device shown in FIG. 24 is a frame signal generating unit for the transmission line 1; 25 is a control unit that controls the processing operations of the entire device; be.

Next, the operation of the above embodiment will be explained. As shown in FIG. 1, the data transmission path 1 is divided into a plurality of channels (time slots) using a time division method, and communication is performed using these channels. First, if there is no data transfer request from any node, the communication monitoring and control device 7 sends a frame Fa, which is composed of a frame header of a certain size and a control time slot 12, as shown in FIG. 2(a). is sent to transmission path 1.

On the other hand, when a data transfer request is made by node 1 (hereinafter referred to as a node number), the communication monitoring and control device 7 uses the common control channel 6, that is, the control time slot 12, to transfer data to the destination node. n information and requests channel allocation. In the communication monitoring control device 7, this information is received in the memory 22, and the information is stored as shown in FIG.
As shown in b), the calculation unit 23 adds time slots 13 and 1 of nodes 1 and n to the remaining frame excluding the frame header 11 of a certain size and the control time slot 12.
Assign 4. Furthermore, the nodes 1 and n are notified of the channel to be used. As a result, the nodes 1 and n that have received the usage channel determination notification can perform data communication with each other based on the structure of the frame Fb sent from the frame generation unit 24.

Next, when a data transfer request is received from node 2 to node l via the control time slot 12 while node 1 and node n are communicating, communication monitoring is performed as shown in FIG. 2(c). The control device 7 assigns time slots 13, 15, and 15 of nodes 1, 2, l, and n to portions corresponding to time slots 13 and 14 in frame Fb in FIG. 2(b).
16, 14, and nodes 1, 2, l,
Notify n of the channel number to be used. As a result, data communication between nodes 1 and n and between nodes 2 and 1 is possible due to the configuration of frame Fc.

On the other hand, when the data communication between the node 2 and the node I is completed, the node 2 that issued the data transfer request sends a completion notification to the control time slot 12. The calculation unit 23 of the communication monitoring and control device 7 that received the termination notification releases the time slots 15 and 16 used by these nodes, changes the frame configuration to frame Fb shown in FIG. 2(b), and A frame is sent from the generation unit 24 to the transmission path 1.

[0015] Similarly, a frame is constructed from a frame header 11 of a certain size, a time slot 12 for communication control, and a time slot allocated only to nodes that have data transfer requests, and the number of nodes that have data transfer requests is increased or decreased. Data communication is performed by changing the size of the time slot assigned to each node.

FIG. 4 is a frame configuration diagram of another embodiment of the present invention. The difference from FIG. 2 is that a certain frame header 1
1, communication control slot 12, and a number of fixed-sized time slots equal to the number of nodes connected to transmission path 1, and allocate time slots only to nodes that have data transfer requests, leaving them in an empty state. Frame Fa is configured such that there are no time slots. That is,
If there is no data transfer request from any node, Figure 4
As shown in FIG. 4(a), all time slots other than frame header 11 are assigned to control slot 12, and when data communication is performed between node 1 and node n, as shown in FIG. 4(b), In addition, except for the frame header 11 and control time slot 12, node 1 and node n are alternately assigned to time slots to configure frame Fb. Furthermore, when performing another communication between node 2 and node l, as shown in FIG. 4(c), nodes 1, 2, l,
Data communication is performed by configuring a frame Fc in which time slots are alternately allocated to time slots.

[0017]

As described above, according to the present invention, the sizes of channels (time slots) constituting a frame are changed, time slots are allocated only to nodes that have data transfer requests, and vacant time slots are used. By eliminating this, we can increase the efficiency of the transmission line.
Another advantage is that large amounts of data can be communicated at high speed.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a TDM loop type network communication system according to the present invention.

FIG. 2 is a diagram showing an example of a frame configuration according to the present invention.

FIG. 3 is a block diagram of the communication monitoring and control device in FIG. 1;

FIG. 4 is a diagram showing another embodiment of the frame structure according to the present invention.

FIG. 5 is a configuration diagram of a conventional loop type network communication system.

FIG. 6 is a frame configuration diagram of a conventional TDM system.

[Explanation of symbols]

1 Data transmission path 2 Node 3 Terminal 4 Channel (time slot) 5 Channel (time slot) 6 Common control channel (control time slot) 7
Communication monitoring control device

Claims (1)

[Claims] 1. A data communication method in which a plurality of nodes to which terminals are connected are connected in a loop through a transmission path, and a communication control device performs data communication between each node in a plurality of time-divided time slots. The communication control device configures the frame sent to the transmission path with a frame header and a control time slot when there is no data transfer request, and a frame header, control time slot, and data transfer request when there is a data transfer request. A data communication method characterized by consisting of time slots assigned only to a certain node.