this way the sequence from bus reset until declaration of the parent child relationships among all the nodes in the network shown in fig2 is completed the flow chart in fig2 will be explained below in the sequence until fig2 since the individual nodes have already been set with information of flags indicating leaves branches and root the flow branches in step s 301 based on the set flag in the operation for assigning ids to the nodes id assignment can be started from each leaf ids are set from smaller numbers from the node number 0 in the order of leaf branch root in step s 302 the number n of leaves n is a natural number in the network is set in step s 303 each leaf requests the root id assignment if there is more than one assignment request the root performs arbitration in step s 304 and assigns an id number to one winning node and informs the losing nodes of the failure result in step s 305 in step s 306 the leaf that has failed to acquire an id issues an id request again to repeat the above operations the leaf that has acquired an id broadcasts the acquired id information to all other nodes in step s 307 upon completion of broadcasting of the id information from one node the number of remaining.