Switching hubs includes switches in a hierarchy type communication network used in a vehicle, the switches respectively include a first section storing a received Identification (ID) number received by one port in a memory as an identifier of the respective switches, and a second section sending a port-specific identifier from each of the other ports in the respective switches by generating the port-specific identifier as a combination of a port number and the received ID number according to a preset rule, thereby enabling a dynamic assignment of an identifier to each of the switches in the communication network.