COMMUNICATION DEVICE

PROBLEM TO BE SOLVED: To eliminate a risk that when a part of multiple units such as a switch fabric made redundant within a communication device is in an idle state in order for power saving, even if a silent failure, i.e. a failure detected for the first time when transmission operation is performed, occurred in the idle unit, it cannot be detected, and therefore, a failure is detected for the first time when a unit, which was an idle unit until then, is operated due to increase in a traffic load or a failure of a working unit, and the number of units necessary to operate may not be secured.SOLUTION: A threshold value is set to an idle state duration, each unit is shifted to a working state if its idle state duration exceeds the threshold value, and a unit that was in a working state until then is shifted to an idle state.