JPH07303116A - Bypass system for abnormality station in token ring communication - Google Patents

Abstract

PURPOSE:To avoid stop of all communication by providing a bypass relay to a transmission line of each station and short-circuiting an input and an output of the station side so as to exclude the effect of an abnormality occurred in one station onto other stations through a token ring communication line. CONSTITUTION:When a transmission disable state is caused in a communication program of each station, each station drives a bypass relay unit 1, and relay contacts a, b of the unit 1 short-circuit input and output of a line side and relay contacts c, d short-circuit input and output of a station side to form a closed loop. A host MPU writes self-diagnosis data to a RAM 4 for the transmission. Transmission data are looped back at bypass relay contacts c, d via a communication LSI 2 and a MODEM 3 and stored once in the RAM 4 through the MODEM 3 and the communication LSI 2 again and then the host MPU compares transmission and reception data. When any abnormality takes place in this case, it is discriminated as an abnormality of a concerned station to connect a bypass and when all equipments are not abnormal, it is discriminated that the cause resides in other stations, and bypassing is released and a channel is connected again to disconnect surely an abnormal station.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a world standard token ring system (IEEE802.4) used for communication lines of computers and the like, in order to avoid all communication failures due to an abnormal station on a data transmission line, The present invention relates to a bypass method for leaving an abnormal station.

[0002]

2. Description of the Related Art A transmission line of a token ring communication system used for a communication line of a system control computer is duplicated and transmitted to both transmission lines, and one of the transmission lines is selected and used by the receiving side of each station. ing. Due to this duplicated transmission line, the transmission line is switched when the token or text cannot be received on the station side for a certain period of time.

When reception failure occurs due to an abnormality on the station side, the line does not recover even if the transmission path is switched. Therefore, when an abnormality is detected by the self-diagnosis function of the station, the transmission path of the abnormal station is bypassed and disconnected. The influence on other stations is excluded.

However, since the self-diagnosis function for discriminating an abnormal portion cannot detect all of them, there is a problem that if not detected, the transmission path is not bypassed and communication is stopped at the abnormal station and all communication is stopped.

[0005]

In the token ring communication system, since all the data passing through the transmission line passes through all the stations on the transmission line, the abnormality of any one of the stations becomes the entire communication abnormality. In some cases, in consideration of the influence of the abnormal station, the bypass system that separates the station in which the abnormality has occurred from the transmission line eliminates communication failure and the influence on other stations, but the self-diagnosis function for detecting the abnormality is limited. Since only abnormalities can be detected, when other abnormalities occur, the bypass function does not work, and there is a problem that communication stops at the abnormal station and all communication is stopped.

An object of the present invention is to operate a bypass function for separating a transmission line from an abnormal station for all abnormalities on the station side, eliminate the influence on other stations, and prevent all communication stoppages.

[0007]

[Means for Solving the Problems] In order to achieve the above object, when all communication stoppages occur, they are detected and all stations perform a closed loop test including bypass relays. The line is connected, and if it is abnormal, the transmission line of the abnormal station is forcibly bypassed.

[0008]

According to the present invention, when transmission failure occurs in the communication program, the input / output on the station side is short-circuited in the bypass relay unit of each station, and a closed loop is formed in the station for self-diagnosis. If the diagnosis result is good, the line is connected again as in the case of the short circuit in the bypass relay unit, and if an abnormality is detected, the line is forcibly bypassed in the bypass relay unit. Therefore, by detecting the abnormal station and disconnecting it from the line, the influence of the abnormal station on all communications can be eliminated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

On the transmission line of each station by token ring communication of the system control computer, the function of short-circuit connection (relay contact a, b) to the input / output on the line side and the input / output on the station side are short-circuited (relay contact c, d), closed loop By-pass relay 1 unit which has two functions that can configure

As described above, in addition to this embodiment, the function of activating the self-diagnosis of the station when transmission failure occurs in the communication program of each station, the function of forcibly bypassing based on the result of the self-diagnosis, and the When transmission to the firmware becomes impossible due to the self-diagnosis function according to the self-diagnosis request from the host side, the host side detects an abnormality of the station, and at the time of detecting the abnormality, each station forcibly activates the bypass signal. This disconnects the station from the transmission path. In this state, the sending side writes the host data to the RAM4 from the host side and sends it after connecting to the receiving side via the bypass relay. The transmission data passes through the transmission side modem 3 of the transmission LSI 2 and is returned by the bypass relay 1, passes through the modem 3 again, and then returns to the reception side of the communication LSI 2. The data received on the receiving side of the communication LSI 2 is temporarily RA
After being stored in M4, it is read by the host side and the transmission data and the reception data are compared.

At this time, if there is an abnormality, the bypass is continued as an abnormality of the station, and if all are abnormal, it is assumed that the other station is the cause of the communication abnormality, and the bypass is stopped and the communication path is reconnected. It is possible to reliably remove the station, and it is possible to completely prevent all communication stoppages due to an abnormal station.

[0013]

According to the present invention, there is an effect that it is possible to avoid all communication failures of a communication line adopting the token ring system due to an abnormal station. Further, the product reliability of the computer or the like which adopts the token ring system is also improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

1 ... Bypass relay, 2 ... Transmission LSI (SCC), 3 ...
Modem, 4 ... RAM.

Claims (1)

[Claims] 1. When all communication failures occur in the token ring communication method, the transmission failure is detected, the station is disconnected from the line, and a closed loop test is performed on the station side including the bypass relay. If there is, connect the line as before,
A bypass system for abnormal stations in token-ring communication, which is characterized by the ability to forcibly bypass an abnormal station if it is abnormal.