In this paper we design DCMA, a novel multicast membership management scheme for data center networks. Unlike traditional protocols like IGMP/MLD, DCMA leverages the characteristics of data center multicast application and the emerging software defined networking (SDN) technique to manage multicast members in an easier and better way. Multicast application master delivers the membership to the SDN controller, and the SDN controller assigns the group addresses in a coordinated way to minimize the forwarding table size in switches. In particular, by formulating the multicast group address allocation problem and capturing the relationship among forwarding entries in different switches, we design both a batch algorithm and an incremental algorithm to allocate the multicast group addresses. Evaluations based on real-world traces show that, DCMA can save almost half multicast forwarding entries in switches compared with random multicast address allocation.

To efficiently utilize their infrastructure and thus increase their revenue, cloud providers need mechanisms to provide resource allocation and performance isolation for different tenants in the shared platform. In particular, network bandwidth sharing is a critical yet still an open problem to most cloud providers. In this paper, we study the problem of virtual machine (VM) allocation under the consideration of providing bandwidth guarantees. We first propose an online allocation algorithm for tenants with homogeneous bandwidth demand, which improves on the accuracy of existing algorithms. Subsequently, we extend it to handle heterogeneous bandwidth demand. Extensive simulations show that our algorithm makes much more efficient utilization of the network resource than existing algorithms, and performs close to the optimal offline allocation.