Optimized Cooperative Streaming in Wireless Mesh Networks

Peer-to-peer video streaming is a valuable technique to reduce the overhead produced by centralized and unicast-based video streaming. Key to the efficiency of a peer-topeer approach is the optimization of the logical distribution topology (the overlay with respect to the underlying network, the underlay). This work studies peer-to-peer streaming in wireless mesh networks for which the underlay is known. We propose an optimized, cross-layer approach to build the peer-to-peer distribution overlay minimizing the impact on the underlay. We design an optimal strategy, which is proven to be NP-complete, and thus not solvable with a distributed, light weight protocol. The optimal strategy is relaxed exploiting the knowledge of the betweenness centrality of the underlay nodes, obtaining two easily implementable solutions applicable to any link-state routing protocol. Simulation and emulation results (experimenting with real applications on a network emulated with the Mininet framework) support the theoretical findings, showing that the relaxed implementations are reasonably close to the optimal solution, and provide vast gains compared to the traditional overlay topology based on Erdös-Rényi models that a peer-to-peer application would build.