Multicast cloud with integrated multicast and unicast content distribution routing

In this paper, we describe the concept and design of "application-layer multicast cloud," the first overlay network design that provides integrated content distribution routing between IP multicast and unicast via a user-configured group of multicast senders and receivers for content distribution across different layer-3 IP multicast groups, content distribution channels, and unicast distribution relay trees, that for the first time allows for application-layer (as opposed to layer-3 or layer-4) control of multicast security, failover, QoS, and bandwidth utilization. None of these were possible before and yet the need for such capabilities is great in Content Distribution Network (CDN) deployments. Note that here "multicast cloud" refers to an "application-layer" user configured entity with (1) a number of properties that govern the IP multicast flow and the interaction between multicast and unicast content distribution, and (2) a set of hosts that can participate in multicast content replication that happens on multiple layer-3 IP multicast groups and across multiple layer-3 IP multicast islands.