Patent ID: 7450526

Claim:
A method of configuring a direction-based Core Based Tree (CBT) for a CBT-based overlay multicast, the method comprising: requesting and receiving information on child nodes pre-subscribed to a core node at an arbitrary terminal node to be subscribed to the CBT; calculating a direction between the terminal node and each of the child nodes and transmitting information on the child node having a minimum resultant value to the core node along with a subscription request message; and comparing the calculated direction between a corresponding child node and the terminal node with the calculated direction between child nodes pre-subscribed to the core node at the core node and subscribing the terminal node to either the child node or a parent node of the corresponding child node in accordance with the comparison to configure the CBT; wherein calculating the direction comprises using internal and external angles and a height of a triangle having respective distances between the core node and two arbitrary nodes adjacent to the core as respective sides of the triangle.