Native multicast datagram delivery using Xcast over IPv6 networks

While traditional multicast is scalable in the sense that they can support very large groups, there are scalability problems when network needs to support a very large number of distinct groups. This paper presents a new alternative scheme, called Xcast6+, which is an extension of Explicit Multicast (Xcast) for an efficient delivery of native multicast datagrams over IPv6 networks. The mechanism incorporates MLDv2 and a new control plane into existing Xcast, and not only does it provide the transparency of traditional multicast schemes to sources and recipients, but it also enhances the routing efficiency in networks. Since intermediate routers do not have to keep track of multicast state, it results in a more efficient and scalable mechanism to deliver native multicast datagrams. Moreover, the seamless integration of Xcast6+ in Mobile IPv6 can support multicast efficiently for mobile nodes (both sources and recipients) over IPv6 networks by avoiding tunnel avalanches and tunnel convergence. Our simulation results show distinct performance improvements of our approach. Our approach can reduce network resources when recipients are clustered in local links (i.e., "subset-dense group").