Optimization of Tree-like Core Overlay in Hybrid-structured Application-layer Multicast
Jianguang Weng · KSII Transactions on Internet and Information Systems · 2012
The tree topology in multicast systems has high transmission efficiency, low latency, but poor resilience to node failures.In our work, some nodes are selected as backbone nodes to construct a tree-like core overlay.Backbone nodes are reliable enough and have strong upload capacity as well, which is helpful to overcome the shortcomings of tree topology.The core overlay is organized into a spanning tree while the whole overlay is of mesh-like topology.This paper focuses on improving the performance of the application-layer multicast overlay by optimizing the core overlay which is periodically adjusted with the proposed optimization algorithm.Our approach is to construct the overlay tree based on the out-degree weighted reliability where the reliability of a node is weighted by its upload bandwidth (out-degree).There is no illegal solution during the evolution which ensures the evolution efficiency.Simulation results show that the proposed approach greatly enhances the reliability of the tree-like core overlay systems and achieves shorter delay simultaneously.Its reliability performance is better than the reliability-first algorithm and its delay is very close to that of the degree-first algorithm.The complexity of the proposed algorithm is acceptable for application.Therefore the proposed approach is efficient for the topology optimization of a real multicast overlay.