JPH0252541A - Data transmission system in lan - Google Patents

Abstract

PURPOSE:To improve the transmission efficiency by giving a token in order to each station and allowing a station holding the token to send a cyclic data and an event data upon the request. CONSTITUTION:A logic ring is formed by stations 1-6, a token is given to the stations 1-6 in order, and when a station receiving the token from the preceding station is a cyclic data transmission designation station, the station sends the cyclic data. Then the presence of a transmission request of an event data is discriminated and when the transmission request exists, the event data is sent and the token takes over the succeeding station. On the other hand, when the station receiving the token is not the cyclic data transmission designation station, the presence of the transmission request of the event data is discriminated and when the transmission request exists, the event data is sent, the token takes over to the succeeding station and when no transmission request of the event data exists, the data is not sent and the token is given to the succeeding station. Thus, one cycle of the cyclic transmission is finished when the token is circulated in the stations 1-6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of the Invention) The present invention relates to a LAN that cyclically transmits data using a token passing method based on a logical ring.
In particular, the present invention relates to a data transmission system in a LAN that allows cyclic data and event data to be transmitted in a mixed manner.

(Summary of the Invention) This invention provides a transmission system that transmits a mixture of cyclic data and event data using a token passing method based on a logical ring. It is designed to transmit event data.

(Prior art and its problems) In a conventional cyclic transmission system in which transmission is controlled by a token passing method based on a logical ring, the order in which stations transmit data is determined, for example, in the order of addresses, and the transmitting station has the same priority as the previous station. After the broadcast was over, it was monitored and the next station would transmit it.

However, in such conventional transmission methods, there are cases where event data, that is, transmission data that occurs at arbitrary timings, is mixed in each station, and where stations transmit only event data. In the case where there is Monitoring has problems such as the time it takes to determine whether data transmission is complete.

(Purpose of the invention) This invention was made in view of the problems mentioned above.
Using a token passing method based on a logical ring, a token (transmission right) is passed to each station in turn, and the station holding the token transmits cyclic data and event data if requested. The purpose of this invention is to eliminate the need for a monitoring timer and to solve the above-mentioned problems.

(Structure and Effects of the Invention) In order to achieve the above-mentioned objects, the present invention provides a cyclic transmission method in which transmission is controlled by a token passing method based on a logical ring, in which a station holding a token can transmit data in response to a request. It is characterized by transmitting click data and event data.

That is, according to the present invention, since the station holding the token is configured to transmit cyclic data and event data in response to a request, each station has a timer that monitors the transmission of event data of the previous station. Since there is no need to have a LAN, this type of LAN can be manufactured at low cost, and since it does not take time to determine whether data transmission is complete, it has the effect of improving transmission efficiency.

(Explanation of Embodiment) Figure 1 shows a logical ring in which transmission is controlled by a token passing method, and according to this logical ring, 1. ing.

In this embodiment, a logical ring is configured by stations 1 to 6, and the token is configured to circulate between stations 1 to 6 in the direction of the arrow within a fixed time and repeat this process. ing.

What is shown in FIG. 2 is an explanatory diagram showing the order of operation of transmitting cyclic data and transmitting event data using the above-mentioned token circulation method. Data transmitting station, station 2,
3 is designated as a transmitting station for cyclic data only, and 4 is designated as a transmitting station for event data.

What is shown in FIG. 3 is a flowchart showing the processing at each node. In the system of the present invention, a logical ring (stations 1 to 6) indicating the order in which tokens are transferred is first formed, and tokens are circulated according to this logical ring, thereby performing cyclic transmission.

Step 100 receives a token from the previous station.

If the station that received the token is the cyclic data transmission designated station (Yes at step 101), cyclic data is transmitted (step 102).

Next, it is determined whether there is a request to send event data (step 103), and if there is a request to send event data, the event data is sent (step 105), and the token is passed to the next station indicated in the logical ring.

On the other hand, if the station that received the token in step 101 is not the cyclic data transmission designated station (No in step 101), the process jumps to step 103, and if there is an event data transmission request, the process proceeds to step 105 to transmit the event data. While passing the token to the next station,
Step 1 when there is no request to send event data
03 negative), pass the token to the next station without transmitting.

Each station thus performs the above operations, and one cycle of cyclic transmission is completed when the tokens have circulated once.

As described above, according to the present invention, it is not necessary for each station to monitor the transmission of event data of the previous station without using a monitoring timer as in the conventional case, and thus this type of LAN can be manufactured at low cost. , transmission efficiency can be improved.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a logical ring using the token passing method, Fig. 2 is an explanatory diagram showing the operational order of cyclic data transmission and event data transmission of tokens that circulate around the logical ring, and Fig. 3 is an explanatory diagram of the operation order of token passing around the logical ring and event data transmission. 3 is a flowchart showing processing. 1~6...stations

Claims (1)

[Claims] 1. In a cyclic transmission method in which transmission is controlled by a token passing method based on a logical ring, a station holding a token transmits cyclic data and event data in response to a request. Characteristic data transmission method in LAN.