On Constructing High Performance Overlay for Layered Streaming in Heterogeneous Networks

This paper presents the mechanism and evaluation of a Qos-aware overlay construction approach for layered streaming, called OCals. The motivation originates from the lack of overlay construction method suitable for layered streaming, because in previous works 1) a newly joining node selects neighbors just based on their network conditions, ignoring a neighbor with good network condition may be unable to provide sufficient layers. 2) Newly joining nodes usually select nodes that can provide good QoS as neighbors to improve its own performance but are not utilized to improve existing poor nodes. Therefore, OCals is proposed, whose basic idea and main contribution come in two-fold: 1) during neighbor selection, existing nodes´ network conditions and providing layers are considered as a whole; 2) OCals guarantees the QoS for new node and also improves the QoS for existing overlay. Ocals is easy to implement with low time cost, and has been implemented within our layered streaming architecture on Internet. Experiments demonstrate that compared with two other classic approaches of SCAMP and Narada, the throughput and packet delay of the layered streaming on top of the overlay constructed by OCals can be remarkably improved, with low time cost for joining/recovery process.