A control apparatus for controlling a network comprising: a path control means (10, 110, 1001) for selecting a communication apparatus (40, 41, 140, 141, 1040, 1041) having an identifier as a destination communication apparatus among a communication apparatus group, based on a connection relationship between the communication apparatus group, which is connected to the network and includes communication apparatuses (40, 41, 140, 141, 1040, 1041) each having the same identifier, and a source communication apparatus (130, 1130) which performs communication using the identifier as a destination address, and setting a process corresponding to a path from the source communication apparatus (130, 1130) to the selected destination communication apparatus (40, 41, 140, 141, 1040, 1041) to a transfer apparatus (1121, 1122, 1124) in the network, characterised in that the path control means (10, 110, 1001) comprises: a first storage means for storing the connection relationship between the communication apparatus and the transfer apparatus (21, 22, 23, 24, 1121, 1122, 1124) which is located in a boundary of the network; a second storage means for storing the communication apparatus having the same identifier among the communication apparatus group by correlating with each transfer apparatus (1121, 1122, 1124) which is located in a boundary of the network or each port provided in the transfer apparatus (1121, 1122, 1124); and a selecting means for searching for the transfer apparatus (1121, 1122, 1124), which is located in a boundary of the network and is connected with the source communication apparatus (130, 1130), from the first storage means when communication using the identifier as a destination address is received, and selecting from the second storage means any one of communication apparatuses in the communication apparatus group which is corresponding to the searched transfer apparatus (1121, 1122, 1124) as the destination communication apparatus. a path control means (10, 110, 1001) for selecting a communication apparatus (40, 41, 140, 141, 1040, 1041) having an identifier as a destination communication apparatus among a communication apparatus group, based on a connection relationship between the communication apparatus group, which is connected to the network and includes communication apparatuses (40, 41, 140, 141, 1040, 1041) each having the same identifier, and a source communication apparatus (130, 1130) which performs communication using the identifier as a destination address, and setting a process corresponding to a path from the source communication apparatus (130, 1130) to the selected destination communication apparatus (40, 41, 140, 141, 1040, 1041) to a transfer apparatus (1121, 1122, 1124) in the network, characterised in that the path control means (10, 110, 1001) comprises: a first storage means for storing the connection relationship between the communication apparatus and the transfer apparatus (21, 22, 23, 24, 1121, 1122, 1124) which is located in a boundary of the network; a second storage means for storing the communication apparatus having the same identifier among the communication apparatus group by correlating with each transfer apparatus (1121, 1122, 1124) which is located in a boundary of the network or each port provided in the transfer apparatus (1121, 1122, 1124); and a selecting means for searching for the transfer apparatus (1121, 1122, 1124), which is located in a boundary of the network and is connected with the source communication apparatus (130, 1130), from the first storage means when communication using the identifier as a destination address is received, and selecting from the second storage means any one of communication apparatuses in the communication apparatus group which is corresponding to the searched transfer apparatus (1121, 1122, 1124) as the destination communication apparatus. a first storage means for storing the connection relationship between the communication apparatus and the transfer apparatus (21, 22, 23, 24, 1121, 1122, 1124) which is located in a boundary of the network; a second storage means for storing the communication apparatus having the same identifier among the communication apparatus group by correlating with each transfer apparatus (1121, 1122, 1124) which is located in a boundary of the network or each port provided in the transfer apparatus (1121, 1122, 1124); and a selecting means for searching for the transfer apparatus (1121, 1122, 1124), which is located in a boundary of the network and is connected with the source communication apparatus (130, 1130), from the first storage means when communication using the identifier as a destination address is received, and selecting from the second storage means any one of communication apparatuses in the communication apparatus group which is corresponding to the searched transfer apparatus (1121, 1122, 1124) as the destination communication apparatus.