An optimized overlay multicast sub-tree rearrangement algorithm

Traditional overlay multicast tree rearrange routing algorithm takes the approach of iterative optimization which is based on the residual degree, However in the sparse residual degree distribution, the proportion of optimization is low. This paper proposes a new algorithm of rerouting that is independent of residual degree, adopting Sorted sub-trees Exchange Strategy instead of residual degree migration strategy. The proposed approach can effectively reduce the overall delay. Experiments show that when remaining degree of the trees is less than 15% of the total, the proposed algorithm would enhance 5% -10% delay optimization ratio. The result can apply to the maintenance of the real-time group multimedia services distribution system, and can provide sustainable Quality of Service(QoS) for long time users.