With the explosive growth of streaming and interactive multimedia applications over the Internet, many approaches have been proposed to stream data effectively over packet switched, best-effort networks. Many use techniques from source and channel coding, implement transport protocols, or modify system architecture in order to deal with the delay, loss, and time-varying nature of the Internet. In this research, we address the packet loss and delay associated with the Internet by proposing a path diversity framework in which multimedia data is streamed via multiple paths to the receiver, leading to higher tolerance against loss and delay.
We investigate two approaches for achieving path diversity for streaming and real time applications over the Internet. For streaming applications, we use multiple senders to stream data to a single receiver while for real time applications, disjoint paths from a sender to a receiver are created using a collection of relay nodes. In the latter approach, we propose a heuristic scheme for selecting a redundant path between a sender and a receiver via a relay node based on information returned from a network tool traceroute. We show with simulations for many Internet-like topologies, that our heuristic scheme is able to find a highly disjoint, redundant path. We further demonstrate that substantial reduction in packet loss can be achieved by dividing packets between the default and the redundant paths.
Within the path diversity framework, we propose a TCP-friendly, receiver-driven protocol for simultaneous video streaming via multiple paths to a single receiver. The TCP-friendly, receiver-driven protocol employs a novel rate allocation scheme and packet partition algorithm. The rate allocation scheme determines the sending rate for each sender based on available network bandwidth, amount of forward error correction (FEC), and channel characteristics in such a way as to minimize the probability of packet loss. The packet partition algorithm ensures that every packet is sent using one and only one path, and at the same time, minimizes the probability of late packets. Using both simulations and actual Internet experiments, we demonstrate the effectiveness of our protocol in reducing packet loss, and hence, achieving higher quality for the streamed media.