Router Assisted Overlay Multicast

While multicasting is considered valuable for content distribution, it is not widely supported on the Internet. Content providers have instead turned to peer assisted content distribution in order to efficiently serve large numbers of clients via unicast, thus removing the bandwidth bottleneck from their side. The redundant unicast transmissions of the same packet are not avoided however, they are just distributed between the peers. Since peer assisted content distribution represents a major fraction of total Internet traffic, a more efficient distribution scheme would be of great interest to users and network operators alike. For this reason, we reconsider overlay multicast as a potential solution for mass content distribution. We present an overlay multicast scheme inspired by Scribe that exploits cooperative access routers so as to improve the multicast content distribution trees produced. We investigate the properties of our scheme compared to both regular Scribe and IP multicast over Internet-like network topologies, via a full fledged simulation platform that can be used as a basis for the realistic evaluation of multicast based content distribution applications.