Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
1998-05-06
2001-06-05
Sheikh, Ayaz (Department: 2155)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C714S004110, C714S811000, C340S870030, C340S870030, C370S254000
Reexamination Certificate
active
06243830
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a state information managing method which is able to manage easily state information of respective communication units and also reduce a communication traffic volume required for management of state information in a communication system wherein a plurality of communication units for exchanging data communication mutually are connected to a bus, and a communication system.
2. Description of the Prior Art
In a communication system in which a plurality of communication units are connected to a bus, respective communication units can exchange data communication mutually. At this time, since internal states of respective communication units are changed with the lapse of time, state information indicating the internal states have been managed by the communication units respectively.
As the state information management method, there has been such a method that, when the data management portion issues a state request to respective communication units, such respective communication units transmits a state response to the data management portion in response to the state request from the data management portion. However, according to this method, since the state request and the state response must be issued from respective communication units, an extensive communication traffic volume has been needed.
Therefore, there has been known the first method to reduce the communication traffic volume of the state request. In the first method, once the state request has been issued after a state information collecting destination has been identified clearly, the communication units which receive such state request have transmitted automatically state reports to the state information collecting destination subsequently every time when their states are changed. According to the first method, the communication traffic volume of the state request can be reduced.
However, according to the above first method, if reports of the state information are generated simultaneously from a plurality of communication units, collision of data has occurred. Therefore, for example, a means for avoiding such collision of data must be provided.
In addition, as the second method to reduce the communication traffic volume of the state request, there has been a method set forth in Patent Application Publication (KOKAI) Sho 64-24538, for example. According to this method set forth in Patent Application Publication (KOKAI) Sho 64-24538, the communication controller for sending out information sets a set of address data of own unit and to-be-sent information in the data portion in the certain communication message, and then plural information are sent out in sequence in compliance with procedure of deciding priority order which is decided by the address data. However, in the method set forth in Patent Application Publication (KOKAI) Sho 64-24538, the information request and the information collection are not carried out simultaneously.
Moreover, as the technology of this type in the prior art, there has been a system set forth in Patent Application Publication (KOKAI) Hei 3-38784. The system set forth in Patent Application Publication (KOKAI) Hei 3-38784 is the loop type communication system in which a plurality of communication frames are always circulated in serial.
Still more, the system set forth in Patent Application Publication (KOKAI) Sho 62-194759 is the communication system in which a plurality of nodes are connected like a loop and signals are transmitted in one way. In this communication system, a series of call setting procedures which are constructed by transmitting additional information necessary for call setting request for the transmitter side node issued from the transmitter side node and call setting allowance or call setting refuse and call setting are transmitted via packet transmission.
However, in the system set forth in Patent Application Publication (KOKAI) Sho 62-194759, individual collection is employed but batch collection is not employed. Therefore, according to the system, it has been difficult to reduce the communication traffic volume.
SUMMARY OF THE INVENTION
The present invention has been made in light of the above circumstances, and it is an object of the present invention to provide a state information managing method which is able to manage easily state information of respective communication units and also reduce a communication traffic volume required for management of the state information, and a communication system.
In order to achieve the above object, according to the present invention, there is provided a state information managing method wherein collecting communication unit in a plurality of communication units are able to collect state information indicating respective states from one or more report communication units except the collecting communication unit to manage their state information in a communication system in which the plurality of communication units are connected to a bus to exchange mutual communication, comprising: a state monitoring step of monitoring the state information of own communication unit in respective report communication units, and rewriting the state information stored in a memory portion into new state information after change if the state information in own communication unit has been changed; a transmitting step of transmitting a recovery command for recovering the state information from the collecting communication unit; a transmitting/receiving step of adding the state information stored in the memory portion and own address to the recovery command and then transmitting the recovery command when respective report communication units receive the recovery command; and a receiving step of receiving the recovery command to which changed state information and their own addresses of respective report communication units are added collectively, by the collecting communication unit.
According to the present invention, in respective report communication units, it is monitored whether or not the state information in own communication unit has been changed, then the state information stored in a memory portion is rewritten if the state information has been changed, then the changed state information and own address are added to the recovery command when respective report communication units receive the recovery command, and then the recovery command is transmitted.
Then, after the recovery command has been transmitted to all the report communication units, the collecting communication unit receives the recovery command to which the changed state information and their own addresses of respective report communication units are added collectively.
In other words, since the collecting communication unit can acquire the state information of respective report communication units by receiving the recovery command only once, the communication traffic volume can be reduced and also collision of the state information sent out from respective report communication units can be avoided.
In the preferred embodiment of the present invention, the state monitoring step rewrites the state information stored in the memory portion into new state information after change if the state information of own communication unit is changed, and then sets a report flag added to the memory portion, and the transmitting/receiving step adds the state information stored in the memory portion and their own addresses to the recovery command and then transmits the recovery command if the report flag has been set when respective report communication units receive the recovery command, and then resets the report flag.
In the preferred embodiment of the present invention, the transmitting/receiving step transmits the recovery command received as it is unless the report flag has been set when respective report communication units receive the recovery command.
According to this embodiment, the report flag is set when the state information has been changed and the report flag is reset when the state informatio
Jean Frantz B.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Sheikh Ayaz
Yazaki -Corporation
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