Path Diversity for Overlay Multicast Streaming

In this paper, we propose a new path-diversity based scheme for application layer multicast streaming over the Internet. Rather than building simple trees as in traditional multicast, we construct multicast k-DAGs, characterized by the property that each receiver has k parents. This multiplicity of parents, not only allows for streaming from multiple sources at the same time, thereby decorrelating losses, but also creates an opportunity to dynamically adapt streaming rates from these senders depending on the existing error conditions in the network. To exploit these possibilities, we use a simple rateallocation algorithm and a packet-partitioning algorithm that allows a receiver to co-ordinate the sending of data from amongst its parents. Our results show that our scheme is effective in dealing with packet losses in the network, and increases the goodput of FEC-coded video data by 15-30%.