Multipath streaming in best-effort networks

Multipath streaming is used by resource intensive applications to stream their data over multiple, disjoint paths, thereby cumulating the resources of the different subpaths. The trend towards application-layer implementations of communication protocols allows the deployment of a multipath streaming protocol in the current Internet. However, because resource availability fluctuates in the Internet, a multipath streaming protocol must be combined with other mechanisms to address these fluctuations, e.g., adaptation. This paper describes two approaches to combine adaptation and multipath streaming. The first approach separates the two mechanisms and thereby allows a multipath streaming that is transparent to the application, whereas the other combines the two mechanisms in the application context. This paper compares the two approaches along various parameters. It shows that the first approach is easier to deploy from an engineering point of view, but the separation of multipath streaming and adaptation yields significant drawbacks. Especially, synchronization problems due to different latencies along the paths that form the multipath setup may lead to a significant drop in the quality of data.