JPH01286541A - Split/transmission system of message in network - Google Patents

Abstract

PURPOSE:To utilize the band of a transmission line effectively by adding information representing the succeeding slot position of each block to a first head slot being a division of the slot and sending the slot. CONSTITUTION:A succeeding packet information part IF is added, in which the information representing a slot position of each succeeding slot is added after an F/M/L bit indicating whether it corresponds to the head (First), the middle or the last of the message only to the initial head packet. A B/I bit representing the busy or the idle state and a data part DATA only are given from a 2nd to a last packet instead. Thus, other header than the B/I bit is not required to the succeeding slot the transmission line band is utilized effectively.

Description

[Detailed Description of the Invention] [Summary] Regarding a message division and transfer method in a network, the purpose of making effective use of transmission path bandwidth is to divide messages into blocks of fixed-length slots that flow on the transmission path on the sending side. , information indicating the slot position of each subsequent block is added to the first divided leading slot and sent. On the receiving side, the receiving side receives the leading slot, analyzes this message, and analyzes and identifies each subsequent slot. and configure it to receive and reassemble messages.

[Industrial Application Field] The present invention relates to a message division and transfer method in a network.

In recent years, networks (e.g. loop networks)
As usage in local areas increases, transmission line speed (bandwidth)
Faster speeds and larger scale networks are being realized. For this reason, loop networks tend to accommodate various types of terminal equipment with different communication speeds in an integrated manner, allowing the network to efficiently transfer messages of various lengths (as many messages as possible as quickly as possible). A method for dividing and forwarding messages is required.

[Conventional technology] FIG. 7 is a diagram showing an example of a loop network.

A communication control device N (node) NA-N in which multiple terminal devices (hereinafter simply referred to as terminals) A-D are connected to each other by a transmission path.
Messages are sent and received via D. The method shown in the figure is called throttling.
The transmission path is divided into several fixed length slots,
Each slot flows in a fixed direction on the loop.

FIG. 8 is a conceptual diagram of message transmission and reception from terminal A to terminal B. A message from the terminal A side is divided into a plurality of blocks, a header is attached to each block, and then inserted into an empty slot on the transmission path and transmitted to the terminal B side. Terminal B analyzes the sent header, extracts only its own block, and reconstructs it as a message.

Each slot is in a packet format as shown in Figure 9, with a B/I pit indicating whether it is used (BUSY) or unused (IDLE), a receiving address part OA, a sending address part SA, and a data slot. LNG indicating the length of valid data in the section
F/M/ which indicates whether the data block in the packet corresponds to the beginning (1" i rst), middle (Middle) or last (last) of the message.
It consists of L bits (header part) and data part. Valid data has a variable length within the data section.

When a node on the loop receives a message to be sent from the terminal that is following it, it receives this message? ! Each block is divided into several blocks, and each block is D
A, SA address, and LNG part are added in the form of a packet and sent out to the transmission route. On the other hand, each node checks the DA address every time a slot in use (a slot with the B/I pit on) arrives from the transmission path, and if it matches the own node address, it receives the DATA part.

Once each block has been received, it is reconfigured as a message and passed on to the succeeding terminal.

[Problems to be Solved by the Invention] In the conventional method, a message is divided into several blocks as described above, and each block is divided into a DA address, an SA
Since control units such as address and LNG units are added and sent to the transmission line, the portion of the transmission line band that is not used for actual data communication (overhead) increases, reducing the effective utilization rate of the transmission line band. This caused the problem of doing so. In the conventional method, ■If the slot length becomes too small than the message length,
The number of divisions increases, and the overhead due to the addition of the control section increases.

(2) Conversely, if the slot length becomes too large than the message length, the overhead of the invalid data portion within the slot will increase.

In networks that process various message lengths, there is a limit to improving the effective utilization of network bandwidth even if the slot length is optimally selected.

The invention was made in view of these problems, and
The purpose of this paper is to provide a method for dividing and forwarding messages in a network that can make effective use of transmission line bandwidth.

[Means for solving one problem] FIG. 1 is a flowchart showing the principle of the method of the present invention. The present invention provides a network system in which a plurality of terminal devices send and receive messages via a communication control device connected to each other via a transmission path, and in which the sending side divides the message into blocks of fixed length slots flowing on the transmission path. ]), a step [2]) of adding information indicating the slot position of each subsequent block to the first divided leading slot and transmitting the message; a step [2]) of receiving the leading slot and analyzing the message; 3]), each subsequent slot analyzed and identified is received, and the message is reconstructed (step [4]).

[Operation 1: Information indicating the slot position of each subsequent block is added to the first divided leading slot and sent.

This eliminates the need for headers other than the B/1 bit in subsequent slots, allowing effective use of the transmission path band.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing an example of a packet format used in the present invention. The difference from the conventional packet format shown in FIG. 9 is that subsequent packet information is added only to the first head packet with information indicating the slot position of each subsequent block after the F/M/L bit. The point is that a section IF has been added. Instead, from the second packet to the final packet, there are only the B/1 pit and the data part. The subsequent packet information section IF is for indicating the position of the subsequent message block (information indicating the number of the packet after passing the first packet).

FIG. 3 is a diagram showing details of the subsequent packet information section IF. When a message is divided into n parts, it consists of n+1 bits, and only the first bit 0 is a bit that indicates whether there is a subsequent packet (it is 1 if there is a subsequent packet, O if there is not), and bits 1 and below are bits that indicate whether there is a subsequent packet or not. Bit 1 is set only in the slot where the packet is inserted. For example, in the case of the example shown in FIG. 4, the second packet following the first packet. Third. . . . Indicates that the n-th slot contains a divided message.

FIG. 5 is an explanatory diagram of message division and transfer according to the present invention, showing a case where a message is divided and transmitted from terminal A to a terminal. The node NA receives the message sent from the terminal and divides it into n blocks. In this case, the node NA takes in information from the transmission path and simultaneously recognizes the B/I states of consecutive n+1gA slots. Then, insert the divided data into empty slots (empty slots in the figure). In this case, in addition to the header shown in FIG. 9 in the first packet, data for the subsequent packet as shown in FIG. 4 is written in the subsequent packet information section IF. As described above, since each node needs to simultaneously analyze the B/r states of n+1 slots, it requires a delay amount of more than n+1 slots, and requires a means (delay circuit) for this purpose. The amount of delay depends on the number of slots n.

FIG. 6 is a diagram showing an example of the configuration of a node used in the present invention. In the figure, 1 is a node and 2 is a terminal. Reference numeral 3 designates a receiving unit that receives messages from the transmission path, and 4 represents a transmitting unit that sends messages to the transmission path. These receiving sections 3.
The transmitting unit 4 has functions such as serial-parallel conversion and interfacing with a transmission path. Reference numeral 5 denotes a delay circuit which receives a message from the receiver 3 and creates a delay time of at least n+1 slots. As the delay circuit 5, a shift register is used, for example.

Reference numeral 6 denotes a received packet judgment circuit that inputs the packet from the delay circuit 5 and judges the header part; 7 receives the output of the delay circuit 5 and the received packet judgment circuit 6; and 8 receives the output of the reception circuit 7. This is a reception buffer for temporary storage, and its output is given to terminal 2.

9 is a control circuit that performs overall control operation; 10 is a delay circuit 5;
This is a packet header manipulation circuit that receives data from the control circuit 9 and a control signal from the control circuit 9 to manipulate the packet header. 12 is a transmitting buffer that temporarily stores messages from the terminal 2; 11 is a transmitting circuit that receives the output of the transmitting buffer 12; and 13 is a select signal from the control circuit 9 that selects either the packet header operation circuit 10 or the transmitting circuit 11. This is a transmission selector that selects and sends it to the transmission section 4.

The node 1 is configured by the components 3 to 13 described above.

Consider the case where the present invention is applied to the loop network shown in FIG. 7 using nodes configured in this manner. Now, consider the case where a message is divided and transferred from terminal A to terminal B. It is assumed that the node NA following the terminal A has stored the message from the terminal A in the transmission buffer 12 in advance. A fixed-length slot is flowing on the transmission path, and the B/r bit in FIG. 2 indicates whether it is in use or not. The received packet determination circuit 6 constantly determines each slot in the delay circuit 5 that has a delay amount of at least n+1 slots, and counts the number of usable packets (unused packets or packets addressed to its own node). are doing. The usable number and its relative position are then communicated to the control circuit 9.

When the control circuit 9 receives a message transmission request from the transmission circuit 11, it is notified of the message length and the destination address. When a predetermined usable packet is secured in this state, the control circuit 9 instructs the packet header operation circuit 10 to output the message length and destination address in the header section of each usable packet in the format shown in FIG. Perform processing such as loading. That is, the relative position of each idle packet (based on the slot position in which the data of the first block is placed) transmitted from the packet determination circuit 6 is written in the packets subsequent to the first packet, and in the same manner as in the conventional system. B/1 pit set, write own node address to DA, write destination address to S△, LNG
Processes such as writing the effective data length are performed. Furthermore, only the B/I bit is set as a header in subsequent packets following the first packet.

If the message transfer ends with only the first packet, the first pit of the subsequent packet information field (see FIG. 4) is set to O, and the following bits are omitted to reduce overhead. Then, at the timing of the data part of each packet, the control circuit 9 switches the transmission selector 13 to the transmission circuit 11 side, and instructs the transmission circuit 11 to load the data in the transmission buffer from the beginning of the message onto the packet and send it to the transmission path. Send to.

On the other hand, in the node NB on the terminal B side that received the first packet of this message, when the received packet determination unit 6 confirms that the B/I pit is set and the own node address is set in DA, the reception circuit 7, and the data portion of this packet is taken into the reception buffer 8 within the range of the effective data length LNG.

Further, at the same time, the subsequent packet information section of the first packet is analyzed, and if there is a subsequent packet, the received packet determination section 6 thereafter instructs the receiving circuit 7 to read the data section of each packet within the range of LNG at that timing, It is taken into the reception buffer 8. Each packet is used to send a new message within the node NB, or is sent out on the transmission path by resetting the B/I pit. The message reconstructed in the receive buffer 8 is sent to the terminal.

In the case of the present invention, a new delay circuit 5 is added within the node, but since the processing speed within the node has been significantly increased due to technological innovation, it does not cause an increase in the loop circuit delay time. .

In the embodiments described above, the present invention is applied to a loop network, but the present invention is not limited to this, and can be similarly applied to other types of bus follow-up systems.

[Effects of the Invention] As described in detail above, according to the present invention, by adding information indicating the slot position of each subsequent block to the first divided leading slot and transmitting the resultant block, the transmission line bandwidth can be used effectively. By making the slot length appropriately short, the effective utilization rate of network bandwidth can be kept extremely high for messages of various lengths. can be maintained.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the principle of the method of the present invention, FIG. 2 is a diagram showing an example of a packet format used in the present invention, FIG. 3 is a diagram showing details of the subsequent packet information section, and FIG. 4 is a diagram showing the details of the subsequent packet information section. 5 is an explanatory diagram of message division and forwarding according to the present invention. FIG. 6 is a diagram illustrating an example of the configuration of a node used in the present invention. FIG. 7 is a diagram illustrating an example of a loop network. FIG. 8 is a conceptual diagram of message transmission and reception from terminal A to terminal B, and FIG. 9 is a diagram showing a conventional example of an intra-slot packet format. Fig. 1 is a flowchart showing the principle of the method of the present invention. Figure 6 shows the loop network 81 Figure 7 shows the message iA reception from t1 France to terminal B Figure 8 shows an example of the packet format in the slot Figure 9
figure

Claims (1)

[Claims] In a network system in which a plurality of terminal devices send and receive messages via a communication control device connected to each other via a transmission path, the sending side divides the message into blocks of fixed length slots that flow on the transmission path. (Step [1]), Add information indicating the slot position of each subsequent block to the first divided leading slot and send it out (Step [2]
), the receiving side receives the first slot and parses this message (step [3]), receives each subsequent slot identified by analysis, and reconstructs the message (step [4]). A method for dividing and transmitting messages in a network characterized by the following.