JPS62117436A - Token monitoring system for loop transmission system - Google Patents

Abstract

PURPOSE:To eliminate the necessity of a stationary monitoring station, by causing plural data transmission stations to monitor the periods of tokens, and by resending the tokens in previously fixed order when the tokens disappear. CONSTITUTION:When a token TK disappears between D-station and E-station, a timer for resending token is actuated at each station. The token resending timer TRA at A-station having the smallest office number is first set to the time-over condition and the token resending is performed by A-station. If A- station cannot make the token resending by some reason, the token resending is performed when the token resending timer TRB of B-station having the second smallest office number is set to the time-over condition. Monitoring of tokens is performed at all data transmission stations in such way and, when a token disappears, the token resending process can be performed at any data transmission station.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a data transmission system in which a plurality of data transmission stations that transmit and receive data are connected in a ring by a transmission path, and a token is received that circulates around the transmission path -L. The present invention relates to a token monitoring method in a loop transmission system using a token passing method in which a station takes the right to transmit data.

<Prior Art> The 1--Kun passing method, which is one of the access methods used in the loop transmission system, uses data transmission stations A, B, etc., as shown in FIG. 8, for example.
・、I? , transmissions 1-8 in which stations are connected in a ring are designated as tokens T
When K circulates around and a data transmission station requesting transmission receives a 1-kun TK, it acquires the right to transmit data. At this time, the data transmission station with the transmission request converts the captured fleet token into a busy token and grants the transmission right.

The token is the same as the network! It disappears due to disturbances in J1, noise, etc. Therefore, in order to have °ζ,l·-kun stably circulate around the network L, station A, which is a monitoring station, constantly monitors the state of the token, and as soon as l·-kun disappears, it retransmits ]·-kun. Do the following.

<Problems to be Solved by the Invention> In the conventional token passing system, monitoring and management of 1-kun is performed centrally by a fixed monitoring station that performs high-performance processing on the network. In this case: 1) If the monitoring station fails, the entire network will go down. In other words, it becomes a danger concentration system.

ii) If the monitoring station has a data transmission function similar to the station, detection of token disappearance may be delayed due to other processing.

There are drawbacks such as:

Means for Solving the Problems> The token monitoring method in the loop transmission system of the present invention uses an I-kun that circulates on a transmission path formed by connecting a plurality of data transmission stages that send and receive data in a ring. In a loop transmission system using a token passing method in which a receiving data transmission station acquires the right to transmit data, the plurality of data transmission stations monitor the circulation of the token, and when the token disappears,
The plurality of data transmission stations notify the disappearance of l.-kun, and a predetermined data transmission station among the plurality of data transmission stations retransmits the token along with the notification according to a predetermined order. It is characterized by

<Example> Fig. 1 shows the basic configuration of a loop transmission system using the present invention, in which five data transmission stations A, 13, 0, I), and E, which transmit and receive data, are connected to a transmission path. R
They are connected in a ring by the ING, and data transmission takes place via adjacent data transmission stations. In this loop transmission system, the token passing method is used as the access protocol, and token management and monitoring are necessary conditions. The token TK is orbiting the transmission path tNGl, and the data transmission station with the transmission request is 1-1-KunT.
When K is received, the transmission right is granted (i#).

Figure 2 shows data transmission stations A, B, etc.
The configuration of a token detection circuit included in station E is shown.

For example, the address-number circuit 2 formed in the Z-8O3IO (manufactured by Sharp Corporation) 1 has one channel that uses the station address for data, and the other channel that uses the token address (FO) for the internal address. Write to comparison circuit. The token bucket that matches in this address-number circuit 2 is stored in the FIFO in the three subsequent stages.
(fast-in-fast-out buffer) 3. Cl) [J 4 can determine whether the token has arrived by examining the contents of this FIFO3.

Figure 3 shows the frame structure of the token bucket, and ta
+ is a fleet token, mountain) is a busy token. However, FLAG is 7E, CRC is a cyclic redundancy check,
ABORT is abort information.

Figure 4 shows data transmission stations A, B, etc.
The processing procedure of station E is shown. First, after turning on the power, each station in the data transmission station performs processing such as initialization (steps #1 to #4). After the network has been started up, each station performs transmission/reception (M data management (step #4). 5
~#8) and token monitoring (step #9) are repeatedly executed.

The procedure for token monitoring processing will be described below.

As shown in Figure 5, first, check the contents of FIFO3,
Is the token T? It is checked whether it is in "I I" 03 (steps #10, #11° #12).

1.- is in FIFO 3, the retransmission timer 1'R is stopped (step #19). If the token disappears due to system synchronization disturbance, noise, etc. and the token is not in InPO4, the retransmission timer TR is started (step 13. #14), and a display indicating that the token has disappeared and notification information Record (
Step #15. #16). And retransmission timer TR
When the time has elapsed, the token is retransmitted (step #17.#]8). The setting time TR of this retransmission timer
is determined by station number x basic retransmission time, and the station numbers are, for example, 1 for A station, 2 for B station, . . . , 5 for 13 stations.

FIG. 6 shows the data flow in the token monitoring process, and when the 1.-kun TK disappears between stations D and E, each station has already started its token retransmission timer. Then, the l·-kun retransmission timer TR^ of station A with the smallest station number times out first, and this station A retransmits the token. Also, as shown in Figure 7, if station A is unable to retransmit the token for some reason,
Station B, which has the next lowest station number, uses timer T for token retransmission.
Token retransmission is performed when Re times out.

In this way, token monitoring is performed at all data transmission stations, and when a token disappears, any data transmission station can process the token retransmission, so there is no specific monitoring station.

<Effects of the Invention> As explained in Section 2, in the present invention, a plurality of data transmission stations constituting the loop transmission system supervise the circulation of tokens. L! When L, , ]--Kun disappears, one of the plurality of data transmission stations forwards I--Kun according to a predetermined order, so that a fixed monitoring station is no longer necessary, and each By standardizing software and hardware in data transmission stations, system costs can be reduced. In addition, since distributed monitoring control is used instead of centralized monitoring control, risks can be distributed and major network failures can be avoided, and recovery from disappearance of tokens can be made faster and processing can be simplified. Furthermore, management data regarding [--kun] can be collected at all data transmission stations, and unstable or dangerous points in the network can be discovered early by comparing the management data of each data transmission station.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the basic configuration of a loop transmission system to which the present invention is applied, Fig. 2 is a block diagram showing the basic configuration of a data transmission station to which the present invention is applied, and Fig. 3 is a diagram showing the basic configuration of a loop transmission system to which the present invention is applied. A diagram showing the frame structure of a token packet in the system, FIGS. 4 and 5 are flowcharts showing the processing procedure of the embodiment of the present invention, and FIGS. 6 and 7 are timing charts showing the data flow of the embodiment of the present invention. FIG. 8 is a diagram showing the configuration of a conventional loop transmission system. Station A, Station B,..., Station E...Data transmission station RING...Transmission line TK...1--Kun Patent applicant Sharp Corporation Agent Patent attorney Nishi 1) New Fig. 3 Figure 6 Figure 7 Figure 8 □

Claims (1)

[Claims] In a loop transmission system using a token passing method in which a data transmission station that receives a token circulating on a transmission path formed by connecting a plurality of data transmission stations that send and receive data in a ring acquires the right to transmit data, the above-mentioned token The plurality of data transmission stations monitor the orbit of the token, and when the token disappears, the plurality of data transmission stations notify the disappearance of the token, and the data transmission stations among the plurality of data transmission stations in accordance with a predetermined order. A token monitoring method in a loop transmission system, characterized in that a predetermined data transmission station retransmits the token along with the notification.