Patent ID: 6975654

Claim:
A network synchronization system for a network wherein a plurality of buses are connected in a tree-like configuration by means of a bridge which has a plurality of portals each of which has a function of a node of the IEEE 1394 standard and to each of which a single bus which complies with the IEEE 1394 standard is connected, said network synchronization system comprising: a network clock reference node functioning as a reference clock source for the entire network and as a network cycle master as prescribed in the IEEE 1394 standard, one of the portals included in said network being set as said network clock reference node; and a local clock reference node provided for each of the other of said plurality of buses other than the bus to which said network clock reference node is connected and serving as a local cycle master prescribed in the IEEE 1394 standard for the bus to which said local clock reference node is not connected, one of the portals connected to said each of the other buses of said plurality of buses which has the least number of hops of nodes up to said network clock reference node being set as said local clock reference node, said local clock reference node including a module for synchronizing a cycle frequency thereof with a cycle frequency of said network clock reference node, wherein said network clock reference node and each said local clock reference node exercise a role decision process to determine its timing role and to set itself up in its timing role.