RELIABILITY ENHANCEMENT IN TREE-SHAPED TOPOLOGY NETWORK

PROBLEM TO BE SOLVED: To provide a method of enhancing the reliability of a network using a tree-shaped topology.SOLUTION: In a method where a lower node selects one of directly adjacent nodes as a backup node in order to arrive at a root node in a tree-type topology, the nodes in the tree-type topology are differentiated by their levels for the root node. For example, a level 1 node is a node where the upper node is the root node, and a level 2 node is a node where the upper node is the level 1 node. All lower node select one of adjacent nodes of minimum level (excepting the upper node) as a backup node. This method is very simple and easy to apply, and the reliability of tree-type topology is maintained and enhanced significantly upon failure of a node or a link.