JPS58171150A - Communication system equivalent to loop - Google Patents

Abstract

PURPOSE:To generate a token from lost token state by making a node to be transmitted transmit a token requesting frame by the disappearance of a token from a loop network to perform superior control, making the highest superior node at the transmission right transmit data and, after completion of the transmission, making the token flow on the loop. CONSTITUTION:When a token flows on the loop at normal state, the titled system receives data to be transmitted to the self-station and transmits data to be transmitted only when the data has higher superior than a transmitting node existing in the token, and the received signal as it is at the time other than said case. When a timer 13 detects that the token does not exist on the loop for a fixed period, the node having transmission data transmits a token requesting signal from a token request frame transmitting part 14 through the transmitting part 15.Consequently, the node having the highest superior obtaines the transmission right and transmits data. After transmitting the data, the station generates a new token.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Technical Field of the Invention The present invention relates to a method of generating a token from a lost token state in a loop peer-to-peer communication system using a token method.

(2) Background of the technology Recently, as a communication method using one transmission line as a loop network, multiple nodes are placed on the loop network, and data is sent and received between the multiple nodes via the loop network. Large-scale communication methods have been proposed.

A problem with such a loop network communication method is to perform loop access such that data transmitted from multiple nodes do not overlap on the loop.

Various methods have been proposed for such loop access.

The most basic method is to specify that only the parent node in a parent-child relationship among the nodes in the loop network has the right to transmit data. This system has the disadvantage that nodes cannot mutually transmit and receive data.

On the other hand, a time slot method has also been proposed in which multiple nodes are connected on an equal basis in a loop network in which each node transmits data using the time slot assigned to it. .

This method has the problem of having to keep the loop length constant.

(3) Problems with the prior art Figure 1 shows loop access to explain the conventional time slot method. In this loop access method, the loop is divided into fixed time slots and the data to be transmitted is divided into fixed time slots. It is designed to be placed in an empty time slot. That is, in FIG. 1, 1 is a loop network with a plurality of nodes 2a.

2b, 2c, 2d, and time slots 3a, 3b with constant transmission time corresponding to the total length of loop 1.

3c, 3d, 3e, and 3f, and each evening, messages to be transmitted from own nodes 2a, 2b, 2c, and 2d to other nodes are divided into im slots, and the data is divided into data units 5 to be sent to the loop. Indicator data 4 for distinguishing between empty data and full data is provided before the message is sent to each time slot. For this reason, in the time slot method, the length of the loop 1 must be kept constant, resulting in the disadvantage that the loop length must be adjusted at each node.

In view of these shortcomings, multiple nodes in an equal relationship are connected to the loop network without adjusting the loop length, and only the node that holds the token, which is the right to transmit data, transmits data. There is a loop peer-to-peer communication system. In the case of such a token system, if a token is lost or disappears from the loop network for some reason, any node will no longer have the right to transmit and will be unable to transmit. When this kind of lost token condition occurs,
If the node that issued the transmission request unilaterally generates and holds a token, multiple tokens will be generated on the loop network, making normal communication impossible.

(4) Purpose of the Invention The purpose of the present invention is to provide a system that can efficiently generate tokens without overlapping when a lost token state occurs and restore the normal system. do.

(5) Structure of the Invention The system of the present invention is a loop network in which a plurality of nodes in an equal relationship are connected to a loop network, and only the node that holds a token, which is the right to transmit data, transmits data. In a communication system, when the token disappears from the loop network, the node that issued the data transmission request sends a token request frame with its own node address, and receives the token request frame sent by another node. At this time, if the priority of the token request frame is higher than the priority of the node, the token request frame is transmitted; if it is lower, it is not transmitted; and when the node receives the token request frame sent by the node, It is characterized in that the token is held and data is transmitted.

(6) Examples of the invention Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 2(a) to (11) are route maps of a loop network for explaining a method of giving priority to multiple nodes. In FIG. 2(a), a loop network 1 has four nodes 2a, 2
When b, 2'c, and 2d are connected and each tail node does not hold a token (the right to transmit data), it monitors whether a token is passed to its own node and sends a "token request frame". Priorities are set for the addresses, for example, 2a>2b>2c>2d.

Next, each node recognizes that the token has disappeared from the loop network if it does not detect the token for a certain period of time using a timer, etc., which will be described later. In this roasted token state, as shown in FIG. If a data transmission request occurs in , nodes 2a and 2C send token request frames R(A) and R(C).The token request frames are, for example, about to be sent as shown in FIG. Hesogu added before data 5 (
HED) B shows the token and token request frame, and also the source node address (SA?). .

It has a destination node address (DA) of 6 and a CRC code (
CRC)9. Delimiter (DE) 10 etc. are added as necessary.

At this time, as shown in FIG. 2 (C1), nodes 2b and 2d receive token request claims R(Δ) and R(C) sent from nodes 2a and 2C, but since there is no particular request, they remain as they are. In this way, as shown in FIG. 2 (dl), the token request frame R(A) from the node 2a is received by the node 2C, and the token request frame R(C) from the node 2C is received by the node 2a. It compares the source node address SAc of the received token request frame from node 2C with its own node address, recognizes that its own node address has a higher priority than SAc, and requests a token from node 2C. absorb.

On the other hand, node 2C requests token R(
The token request R(A) received after comparing the sender node address SAa of A) with the own node address and recognizing that the own node address has a lower priority is transferred to the token request R(A) shown in FIG.
The data is relayed as is on the loop as shown in ll).

Node 2d receives the token request frame R(A) from node 2a as shown in FIG.

As shown in FIG. 2 (gI), the node 2a receives the token request frame R(A) sent by its own node and holds the token.

Next, as shown in FIG. 2(h), the node 2a receives the data 5a.
is sent.

When the node 2a finishes transmitting the data 5a, the node 2a returns to FIG.
), the token frame T (A) is looped 1 as shown in
Send upward.

If there is data to be sent, node 2b absorbs the token frame T (A) as shown in Fig. 2 (j), and node 2b
sends data 5b as shown in Figure 2(k), and if there is no data to be sent, loop 1 continues as shown in Figure 2(1).
The upper token frame T (A) is relayed.

Such operations are sequentially performed at nodes 2c and 2d.

FIG. 4 shows an example of the configuration of the plurality of nodes described above, and the priority communication method of the present invention will be explained based on this system diagram.

When each of the above-mentioned nodes 2a, 2b, 2c, and 2d does not hold a token, it monitors whether or not the token is delivered to its own node, operates the timer 13, and transfers the received token to the transmitter 11. The detection check unit 12 checks the token, and if the token detection check unit does not detect the token for a predetermined period of time set by the timer, it determines that the token in the loop network 1 has disappeared and is in the roast token state, and the data to be sent from each node is determined. If there is, the token detection check unit instructs the token request frame transmitting unit 14 to request a token request frame (see FIG. 3), so that the token request frame R (see FIG. 3) is sent from the transmitting unit 15.
A), R(C), etc. are sent to the loop network 1. The node that sent the token request frame monitors the received data in the receiving unit 11, and if it receives that the token request frame sent by itself has returned after going around the loop network 1, it holds the token and detects the token. The checking unit 12 gives an instruction to the data transmitting unit 16 to send the data 5a.

5b is sent to the loop network through the transmitter 15.

When the sending of the data 5a and 5b is completed, the token sending section 17 is instructed to send out the token T(A) through the sending section 15 to the loop network. Furthermore, when the receiving unit 11 receives a token request frame sent by another node, it compares the source node address (SA) 7 with the address of its own node, and detects a token if its own node address is higher by checking the priority order. If the checking unit 12 makes a judgment, it absorbs the received token request frame and does not send out a token request frame from another node to the loop network 1.

If the token detection check unit determines that the source node address of the received token request frame has a higher priority than its own node address, it sends the received token request frame as is to the transmitter and sends it out to the loop network. do.

When a node that does not transmit a token request frame receives a token request frame sent by another node in the receiving section 11, the token detection check section 12 determines the token request frame and relays the token request frame as it is to the loop network from the transmitting section 15. Ru.

(7) Effects of the Invention As explained in detail above, according to the method of the present invention, when a token disappears for some reason in the token method, when multiple nodes simultaneously enter the token holding state, only one Since only one node is given a token, there is no confusion in transmission, and the data to be transmitted is not limited as in the case of time slots, which has the effect of configuring a loop network that can communicate with each other.

[Brief explanation of drawings]

FIG. 1 is a route map of a conventional time slot type loop network, FIG. 2 (al to (11) is a route diagram explaining the operation of the token type loop network of the present invention, and FIG. FIG. 4 is a system diagram of each node connected to the loop network of the present invention. 1--・JL/- loop network, 2a, 2b, 2c, 2d・
・・Node, 3a, 3b, 3c, 3d-・
・Time slot, 5.5a, sb...data,
R(A), R(C)...Token request frame, T(A)...Token frame, 6
(DA)...Destination node address, 7 (S
A) ... Source node address. ≦ habit

Claims (1)

[Claims] A plurality of nodes in an equal relationship are connected to a loop network,
In a loop peer-to-peer communication system in which only a node that holds a token, which is the right to transmit data, transmits data, when the token disappears from the loop network, the node that issued the data transmission request is automatically When sending a token request frame having a node address and receiving a token request frame sent by another node, if the priority of the token request frame is higher than the priority of the node, send the token request frame. However, if the token is small, the token is not transmitted, and when the token request frame transmitted by the node is received, the token is held and data is transmitted.