Patent ID: 7366114

Claim:
A method for performing a process associated with a QoS-guaranteeing multi-path in a path-based communication network having a plurality of nodes, comprising the steps of: a) determining a start node, a destination node and a requirement condition associated with a reference cost consumed in a range from the start node to the destination node; b) creating a first tree adapting the start node as its root and a second tree adapting the destination node as its root, including nodes close to the start node in a first node group, and including nodes close to the destination node in a second node group; c) selecting a node having a minimum cost associated with the roots from among a plurality of nodes contained in the first and second node groups, and including the selected node having the minimum cost in a tree of a corresponding root; d) if the selected node included in the tree at the step (c) is also included in the first and second trees, and a cost consumed in the range from the start node to the destination node on the basis of the selected node is less than the reference cost, providing a corresponding path associated with the cost; e) including a nearby node of the selected node in a node group having the selected node when the selected node included in the tree at the step (c) is also included in either one of the first and second trees, comparing two paths ranging from a root to the nearby node when the nearby node is previously included in the node group, and deleting a link of a cheaper one of the two paths; and f) determining whether there is a node contained in the first node group and the second node group, repeatedly performing a process from the step (c) when the node is found in the first and second node groups, or terminating the process from the step (c) when no node is found in the first and second node groups.