Communication apparatus and program provided with failure determining method and function

A transmission apparatus in an information system including the transmission apparatus for transmitting control information and a reception apparatus connected to the transmission apparatus in such a manner as to enable information to be transmitted and received for receiving the control information, the reception apparatus transmitting response information to the received control information, the transmission apparatus comprising:

• a first acquisition unit obtaining, as a first clock time, a clock time of the most recently transmitted control information if the response information to the control information cannot be obtained within a predetermined time period;
• a second acquisition unit obtaining, as a second clock time, later one of a clock time of the response information most recently transmitted by the reception apparatus and a clock time of the control information most recently received by the reception apparatus;
• and
• a determination unit determining a failure location based on the first clock time and the second clock time.

A program operable to drive a transmission apparatus in an information system including the transmission apparatus for transmitting control information and a reception apparatus connected to the transmission apparatus in a manner allowing information transmission and reception for receiving the control information, the reception apparatus transmitting response information to the received control information, to execute:

• an operation of obtaining, as a first clock time, a clock time of the most recently transmitted control information if the response information to the control information cannot be obtained within a predetermined time period;
• an operation of obtaining, as a second clock time, later one of a clock time of the response information most recently transmitted by the reception apparatus and a clock time of the control information most recently received by the reception apparatus;
• and
• an operation of determining a failure location based on the first clock time and the second clock time.