According to an embodiment, a communication apparatus controls controllable nodes. The apparatus includes an acquisition unit and a generation unit. The acquisition unit acquires at least one of a first evaluation value indicating an occurrence frequency of a control request to a target controllable node and a second evaluation value indicating an occurrence frequency of communication error at the target controllable node. The generation unit generates identification information to be assigned to control the target controllable node in a manner such that a bit length of the identification information becomes shorter as at least one of the first evaluation value and the second evaluation value increases.