Algorithms and stability analysis for content distribution over multiple multicast trees

Abstract

The paper investigates theoretical issues in applying the universal swarming technique to efficient content distribution. In a swarming session, a file is distributed to all the receivers by having all the nodes in the session exchange file chunks. By universal-swarming, not only all the nodes in the session, but also some nodes outside the session may participate in the chunk exchange to improve the distribution performance. We present a universal swarming model where the chunks are distributed along different Steiner trees rooted at the source and covering all the receivers. We assume chunks arrive dynamically at the sources and focus on finding stable universal swarming algorithms. To achieve the throughput region, universal swarming usually involves a tree-selection subproblem of finding a min-cost Steiner tree, which is NPhard. We propose a universal swarming scheme that employs an approximate tree-selection algorithm. We show that it achieves network stability for a reduced throughput region, where the reduction ratio is no more than the approximation ratio of the tree-selection algorithm. We propose a second universal swarming scheme that employs a randomized tree-selection algorithm. It achieves the throughput region, but with a weaker stability result.

Content distribution by multiple multicast trees and intersession cooperation: Optimal algorithms and approximations

“…We now briefly discuss additional related work. The work in [28] focuses on the queueing process when the universal swarming technique is applied to content delivery. It investigates the stability of the queues under the proposed algorithms and the analytical tool is the Lyapunov drift analysis about Markov processes.…”