MiniForest: Distributed and Dynamic Multicasting in Datacenter Networks

The emerging cloud applications require group communications. For these applications, multicast is a better choice than unicast, because it can significantly improve the performance by eliminating the duplicated packets generated by servers. However, existing multicast schemes for datacenters are either based on IP multicast or centralized scheduling. IP multicast is inefficient for datacenters as it cannot take full advantage of the multipath property. And centralized schemes suffer from single-point failure and scalability problems. To solve these problems, we propose MiniForest, a distributed multicast framework for large-scale datacenter networks. It consists of new routing algorithms and a dynamic group management mechanism. A new address mapping solution is then designed for compatibility to existing upper-layer applications. Based on the mapping solution, we propose an efficient load balancing strategy, with which a minimal forest is constructed for all multicast trees. To study the performance of the new multicast scheme in theory, we further provide an analytical model for Clos-based datacenter networks and analyze the overloading behaviors from a new perspective. We show that the distributed scheme can be used in any size of datacenters. It has much lower complexity and better performance than centralized schemes.